Obstentrics_Williams

Obstentrics_Williams. In the olowingpages I have attempted to set orth, as brily as seemed to be consistent with thoroughness, the scientic basis or and the practical application of the obstetrical art. At the same time, I have endeavored to present the more practical aspects of obstetrics in such a manner as to be of direct service to the obstetrician at the bedside. -J. Whitridge Williams (1903) So reads the introduction to Williams' irst edition of this textbook, Obstetrics-A Text-Book or the Use of Students and Practitioners. In this 25th edition, we strive to follow the tenets described by Williams. And, each chapter begins with a quote from his original textbook.


Obstentrics_Williams

Obstentrics_Williams. he science and clinical practice of obstetrics is concerned with human reproduction. hrough quality perinatal care, the specialty promotes the health and well-being of the pregnant woman and her fetus. Such care entails appropriate recognition and treatment of complications, supervision of labor and delivery, initial care of the newborn, and management of the puerperium. Postpartum care promotes health and provides family planning options. he importance of obstetrics is relected by the use of maternal and neonatal outcomes as an index of the quality of health and life among nations. Intuitively, indices that reflect poor obstetrical and perinatal outcomes would lead to the assumption that medical care for the entire population is lacking. With those thoughts, we now provide a synopsis of the current state of maternal and newborn health in the United States as it relates to obstetrics.


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Obstentrics_Williams. The National Vital Statistics System of the United States is the oldest and most successful example of intergovernmental data sharing in public health. This agency collects statistics through vital registration systems that operate in various jurisdictions. These systems are legally responsible for registration of births, fetal deaths, deaths, marriages, and divorces. Legal authority resides individually with the 50 states; two regions-the District of Columbia and New York City; and ive territoriesAmerican Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the Virgin Islands. The standard birth certificate was revised in 1989 to include more information on medical and lifestyle risk factors and obstetrical practices. In 2003, an extensively revised Standard Certificate of Live Birth was implemented in the United States. The enhanced data categories and speciic examples of each are summarized in Table


Obstentrics_Williams

Obstentrics_Williams. By 2013,i35 states had implemented the revised birth certificate representing 76 percent of all births (MacDorman, 2015). Importantly, the 2003 version of the population death certificate contains a pregnancy checkbox to eventually be implemented by all states a oseph, 2017). The uniform use of standard deinitions is encouraged by the World Health Organization as well as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (2017). Such uniformity allows data comparison not only between states or regions of the country but also between countries. Still, not all deinitions are uniformly Overview of Obstetrics TABLE 1-1. General Categories of New Information Added to the 2003 Revision of the Birth Certificate Risk factors in pregnancy-Examples: prior preterm birth, prior eclampsia Obstetrical procedures-Examples: tocolysis, cerclage, external cephalic version


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Obstentrics_Williams. Labor-Examples: noncephalic presentation, glucocorticoids for fetal lung maturation, antibiotics during labor Delivery-Examples: unsuccessful operative vaginal delivery, trial of labor with prior cesarean delivery Newborn-Examples: assisted ventilation, surfactant therapy, congenital anomalies applied. For example, the American College of Obstetricians and Gynecologists recommends that reporting include all fetuses and neonates born weighing at minimum 500 g, whether alive or dead. But, not all states follow this recommendation. Speciically, 28 states stipulate that fetal deaths beginning at 20 weeks' gestation should be recorded as such; eight states report all products of conception as fetal deaths; and still others use a minimum birthweight of 350 g, 400 g, or 500 g to deine fetal death. To further the confusion, the National Vital Statistics Reports tabulates fetal deaths from gestations that are 20 weeks or older (Centers for Disease Control and Prevention, 2016). his is


Obstentrics_Williams

Obstentrics_Williams. death. To further the confusion, the National Vital Statistics Reports tabulates fetal deaths from gestations that are 20 weeks or older (Centers for Disease Control and Prevention, 2016). his is problematic because the 50th percentile for fetal weight at 20 weeks approximates 325 to 350 g-considerably less than the 500-g deinition. Indeed, a birthweight of 500 g corresponds closely with the 50th percentile for 22 weeks' gestation.


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Obstentrics_Williams. Deinitions recommended by the National Center for Health Statistics and the Centers for Disease Control and Prevention are as follows: Perinatal period. The interval between the birth of a neonate born after 20 weeks' gestation and the 28 completed days after that birth. When perinatal rates are based on birthweight, rather than gestational age, it is recommended that the perinatal period be deined as commencing at the birth of a 500-g neonate. Birth. he complete expulsion or extraction from the mother of a fetus after 20 weeks' gestation. As described above, in the absence of accurate dating criteria, fetuses weighing < 500 g are usually not considered as births but rather are termed abortuses for purposes of vital statistics. Birthweight. The weight of a neonate determined immediately after delivery or as soon thereafter as feasible. It should be expressed to the nearest gram.


Obstentrics_Williams

Obstentrics_Williams. Birthweight. The weight of a neonate determined immediately after delivery or as soon thereafter as feasible. It should be expressed to the nearest gram. Birth rate. The number of live births per 1000 population. Fertility rate. The number of live births per 1000 females aged 15 through 44 years. Live birth. he term used to record a birth whenever the newborn at or sometime after birth breathes spontaneously or shows any other sign of life such as a heartbeat or deinite spontaneous movement of voluntary muscles. Heartbeats are distinguished from transient cardiac contractions, and respirations are diferentiated from fleeting respiratory efforts or gasps. Stillbirth or fetal death. The absence of signs of life at or after birth. Early neonatal death. Death of a liveborn neonate during the irst 7 days after birth. Late neonatal death. Death after 7 days but before 29 days.


Obstentrics_Williams

Obstentrics_Williams. Early neonatal death. Death of a liveborn neonate during the irst 7 days after birth. Late neonatal death. Death after 7 days but before 29 days. Stillbirth rate or fetal death rate. The number of stillborn neonates per 1000 neonates born, including live births and stillbirths. Neonatal mortality rate. The number of neonatal deaths per 1000 live births. Perinatal mortality rate. he number of stillbirths plus neonatal deaths per 1000 total births. Infant death. All deaths of liveborn infants from birth through 12 months of age. Infant mortality rate. The number of infant deaths per 1000 live births. Low birthweight. A newborn whose weight is <2500 g. Very low birthweight. A newborn whose weight is < 1500 g. Extremely low birthweight. A newborn whose weight is < 1000 g.


Obstentrics_Williams

Obstentrics_Williams. Low birthweight. A newborn whose weight is <2500 g. Very low birthweight. A newborn whose weight is < 1500 g. Extremely low birthweight. A newborn whose weight is < 1000 g. Term neonate. A neonate born any time ater 37 completed weeks of gestation and up until 42 completed weeks of gestation (260 to 294 days). The American College of Obstetricians and Gynecologists (2016b) and Society for MaternalFetal Medicine endorse and encourage specific gestational age designations. Eary term refers to neonates born at 37 completed weeks up to 386/7 weeks. Full term denotes those born at 39 completed weeks up to 406r weeks. Last, late term describes neonates born at 41 completed weeks up to weeks. Preterm neonate. A neonate born before 37 completed weeks (the 259th day). A neonate born before 34 completed weeks is early preterm, whereas a neonate born between 34 and 36 completed weeks is late preterm.


Obstentrics_Williams

Obstentrics_Williams. Postterm neonate. A neonate born anytime after completion of the 42nd week, beginning with day 295. Abortus. A fetus or embryo removed or expelled from the uterus during the first half of gestation-20 weeks or less, or in the absence of accurate dating criteria, born weighing <500 g. Induced termination of pregnancy. The purposeful interruption of an intrauterine pregnancy that has the intention other than to produce a liveborn neonate and that does not result in a live birth. This deinition excludes retention of products of conception following fetal death. Direct maternal death. he death of the mother that results from obstetrical complications of pregnancy, labor, or the puerperium and from interventions, omissions, incorrect treatment, or a chain of events resulting from any of these factors. An example is maternal death from exsanguination after uterine rupture.


Obstentrics_Williams

Obstentrics_Williams. Indirect maternal death. A maternal death that is not directly due to an obstetrical cause. Death results from previously existing disease or a disease developing during pregnancy, labor, or the puerperium that was aggravated by maternal physiological adaptation to pregnancy. An example is maternal death from complications of mitral valve stenosis. Nonmaternal death. Death of the mother that results from accidental or incidental causes not related to pregnancy. An example is death from an automobile accident or concurrent malignancy.


Obstentrics_Williams

Obstentrics_Williams. Nonmaternal death. Death of the mother that results from accidental or incidental causes not related to pregnancy. An example is death from an automobile accident or concurrent malignancy. Maternal mortality ratio. The number of maternal deaths that result from the reproductive process per 100,000 live births. Used more commonly, but less accurately, are the terms maternal mortaliy rate or maternal death rate. The term ratio is more accurate because it includes in the numerator the number of deaths regardless of pregnancy outcome-for example, live births, stillbirths, and ectopic pregnancieswhereas the denominator includes the number of live births. Pregnancy-associated death. The death of a woman, from any cause, while pregnant or within 1 calendar year of termination of pregnancy, regardless of the duration and the site of pregnancy.


Obstentrics_Williams

Obstentrics_Williams. Pregnancy-associated death. The death of a woman, from any cause, while pregnant or within 1 calendar year of termination of pregnancy, regardless of the duration and the site of pregnancy. Pregnancy-related death. A pregnancy-associated death that results from: (1) complications of pregnancy itself, (2) the chain of events initiated by pregnancy that led to death, or (3) aggravation of an unrelated condition by the physiologicalior pharmacological efects of pregnancy and that subsequently caused death.


Obstentrics_Williams

Obstentrics_Williams. According to the Centers for Disease Control and Prevention (CDC), the fertility rate of women aged 15 to 44 years in the United States in 2015 was 62.5 live births per 1000 women (Martin, 2017). This rate began slowly trending downward in 1990 and has now dropped below that for replacement births. This indicates a population decline (Hamilton, 2012). There were 3.98 million births in 2015, and this constituted the lowest birth rate ever recorded for the United States-12.3 per 1000 population. The birth rate decreased for all major ethnic and racial groups, for adolescents and unmarried women, and for those aged 20 to 24 years. For women older than 30 years, the birth rate rose slightly. Almost half of newborns in 2010 in the United States were minorities: Hispanic-25 percent, AfricanAmerican-14 percent, and Asian-4 percent (Frey, 2011).


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Obstentrics_Williams. he total number of pregnancies and their outcomes in 2015 are shown in Table 1-2. According to the Guttmacher Institute (2016b), 45 percent of births in the United States are unintended at the time of conception. Importantly, the overall proportion of aExciudes spontaneous abortions and ectopic pregnancies. Data from Martin, 201l7. unintended births has declined only slightly since 2001. Unmarried women, black women, and women with less education or income are more likely to have unplanned pregnancies. In Table 1-2, induced abortion information derives from CDC abortion surveillance data from 45 states combined with Guttmacher Institute data on induced abortion. hese data have been collected beginning in 1976. Since Roe v. Wade legalization of abortion, more than 46 million American women have chosen legalized abortions. As discussed later, this provides a compelling argument for easily accessible family planning.


Obstentrics_Williams

Obstentrics_Williams. Several indices are used to assess obstetrical and perinatal outcomes as measures of medical care quality. As noted, the perinatal mortality rate includes the numbers of stillbirths and neonatal deaths per 1000 total births. In 2013, the perinatal mortality rate was 9.98 per 1000 births (Fig. 1-1) (MacDorman, 2015). There were 25,972 fetal deaths at gestational ages of 20 weeks or older. Fetal deaths at 28 weeks or more have been declining since 1990, whereas rates for those between 20 and 27 weeks are static (Fig. 1-2). By way of comparison, there were a total of 19,041 neonatal deaths in 2006-meaning that nearly 60 percent of the perinatal deaths in the United States were fetal.


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Obstentrics_Williams. here were 6.1 infant deaths per 1000 live births in 2013 compared with 6.8 in 2001 (MacDorman, 2015). The three leading causes of infant death-congenital malformations, low birthweight, and sudden infant death syndrome-accounted for almost half of all deaths (Heron, 2015). Infants born at the lowest gestational ages and birthweights add substantively to these mortality rates. For example, more than half of all infant deaths in 2005 were in the 2 percent of infants born before FIGURE ,A-, Perinatal mortality rates: United States, 2000-2013. (Reproduced with permission from MacDorman MF, Gregory EC: Fetal and perinatal mortality: United States, 2013. Natl Vital Stat Rep. 2015 Jul 23;64(8):1-24.) 0..C ::l� 0 Con , .�A.� 8.s


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Obstentrics_Williams. (Reproduced with permission from MacDorman MF, Gregory EC: Fetal and perinatal mortality: United States, 2013. Natl Vital Stat Rep. 2015 Jul 23;64(8):1-24.) 0..C ::l� 0 Con , .�A.� 8.s FIGURE 1-2 Fetal and neonatal deaths: United States, 2000-2013. (Modified with permission from MacDorman MF, Gregory EC: Fetal and perinatal mortality: United States, 2013. Natl Vital Stat Rep. 2015 Jul 23;64(8):1-24.) 32 weeks' gestation. Indeed, the percentage of infant deaths related to preterm birth increased from 34.6 percent in 2000 to 36.5 percent in 2005. When analyzed by birthweight, two thirds of infant deaths were in low-birthweight neonates. Of particular interest are infants with birthweights <500 g, for whom neonatal intensive care can now be ofered.


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Obstentrics_Williams. As shown in Figure 1-3, maternal mortality rates dropped precipitously in the United States during the 20th century. Pregnancy-related deaths are so uncommon as to be measured per 100,000 births. The CDC (2017a) has maintained data on pregnancy-related deaths since 1986 in its Pregnancy Mortality Surveillance System. In the latest report, Creanga and coworkers (2017) described 2009 pregnancy-related deaths during the period from 2011 to 2013. Approximately 5 percent were early-pregnancy deaths due to ectopic gestation or abortive outcomes. he deadly obstetrical triad ofhemorrhage, preeclampsia, and infection has accounted for a third of all deaths (Fig. 1-4). hromboembolism, cardiomyopathy, and other cardiovascular �CD ""..D FIGURE 1-3 Maternal mortality rates for the United States, 19502003. (Data from Berg, 2010; Hoyert, 2007.) 11.4 �Yuf 11.8 �� � .��t ,��o Cause of pregnancy-related deaths


Obstentrics_Williams

Obstentrics_Williams. FIGURE 1-3 Maternal mortality rates for the United States, 19502003. (Data from Berg, 2010; Hoyert, 2007.) 11.4 �Yuf 11.8 �� � .��t ,��o Cause of pregnancy-related deaths FIGURE 1-4 Six common causes of pregnancy-related deaths for the United States, 2006-2010. (Data from Creanga, 2015.) disease together accounted for another third. Other signii-. cant contributors were amnionic luid embolism (5.3 percent) and cerebrovascular accidents (6.2 percent). Anesthesia-related deaths were at an all-time low-only 0.7 percent. Similar causes were reported for selected cohorts for years 2008 to 2009 and 2013 to 2014 (MacDorman, 2017).


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Obstentrics_Williams. Shown in Figure 1-5, the pregnancy-related mortality ratio of 23.8 per 100,000 live births in 2014 is the highest during the previous 40 years. And, according to the Institute ofHealth Metrics, it was 28 per 100,000 in 2013 (Tavernise, 2016). This rise simply may be that more women are dying, however, other factors explain this doubling of the rate from 1990 to 2013 aoseph, 2017). The irst is an artiicial elevation caused by the International Statistical Classiication of Diseases, 10th Revision (ICD-I0), implemented in 1999. Second, improved ..C-) ) .=19 FIGURE 1-5 Estimated maternal mortality rates in 48 states and the District ofColumbia. (Data from MacDorman, 2016.) Overview of Obstetrics 14.6 13.6


Obstentrics_Williams

Obstentrics_Williams. FIGURE 1-5 Estimated maternal mortality rates in 48 states and the District ofColumbia. (Data from MacDorman, 2016.) Overview of Obstetrics 14.6 13.6 FIGURE 1-6 Trends in maternal mortality ratio (per 100,000 live births) by race: United States, 2005-2014. (Data from Moaddab, 2016.) reporting definitely contributes to the rise (MacDorman, 2016b, 2017). In the past, maternal deaths were notoriously underreported (Koonin, 1997). Third, and related to the second explanation, the rate of rise is at least partially due to the revised death certificate and its pregnancy checkbox described earlier (Main, 2015). Fourth, the number of pregnant women with severe chronic health conditions, which place women at higher risk, is greater (Centers for Disease Control and Prevention, 2017a). Finally, the increased proportion of births to women older than 40 years contribute to higher mortality rates (MacDorman, 2017).


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Obstentrics_Williams. Whatever the cause, the apparent sharp rise of the maternal mortality rates has galvanized the obstetrical community to action (Chescheir, 2015). According to Barbieri (2015), the Joint Commission has recommended that birthing centers establish standardized protocols and implement simulation eforts. D' Alton and colleagues (2016) described eforts of a working group to lower morbidity and mortality rates. Another consideration is the obvious disparity of higher mortality rates among black, Hispanic, and white women as shown in Figure 1-6. Racial disparities translate to health care availability, access, or utilization (Howell, 2016; Moaddab, 2016). And, maternal mortality is disparately high in rural compared with metropolitan areas (Maron, 2017).


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Obstentrics_Williams. Importantly, many of the reported maternal deaths are considered preventable. Berg and colleagues (2005) estimated that this may be up to a third of pregnancy-related deaths in white women and up to half of those in black women. In one evaluation of an insured cohort, 28 percent of 98 maternal deaths were judged preventable (Clark, 2008). hus, although significant progress has been made, further eforts are imperative for obstetrics in the 21 st century.


Obstentrics_Williams

Obstentrics_Williams. his serves as another measure to guide prevention eforts. Lowering medical error rates serves to diminish risks for maternal mortality or severe maternal morbidity. The terms near misses or close calls were introduced and defined as unplanned events caused by error that do not result in patient injury but have the potential to do so (Institute for Safe Medication Practices, 2009). hese are much more common than injury events, but for obvious reasons, they are more diicult to identiy and quantiy. Systems designed to encourage reporting have been installed in various institutions and allow focused safety eforts (Clark, 20i12; Main, 2017; Shields, 2017). The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine (20 16f) have provided lists of suggested screening topics for this purpose.


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Obstentrics_Williams. Several data systems now measure indicators of unplanned events caused by errors that have injurious potential. This evolution followed inadequacies in the ability of hospitalization coding to reflect the severity of maternal complications. Thus, coding indicators or modifiers are used to allow analysis of serious adverse clinical events (Clark, 2012; King, 2012). Such a system was implemented by the World Health Organization. It has been validated in Brazil and accurately reflects maternal death rates (Souza, 2012). Similar systems are in use in Britain as the UK Obstetric Surveilance System-UKOSS (Knight, 2005,i2008). In the United States, one example is the National Partnership for Maternal Safety (D'Alton, 2016; Main, 2015).


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Obstentrics_Williams. To study severe morbidity, the CDC analyzed more than 50 million maternity records from the Nationwide Inpatient Sample from 1998 to 2009 (Callaghan, 2012). They used ICD9-CM codes and reported that 129 per 10,000 of these gravidas had at least one indicator for severe morbidity (Table 1--).hus, for every maternal death, approximately 200 women experience severe morbidity. he CDC (20 17b) estimates that 65,000 women per year have such maternal morbidity. These numbers are greatest in smaller hospitals with < 1000 deliveries annually (Hehir, 2017). Finally, as with mortality rates, there are serious racial and ethnic disparities for severe maternal morbidity, and black women are disproportionately afected (Creanga, 2014). Various topics have been in the forefront for obstetrical providers in the 4 years since the last edition of this textbook. In the following, we discuss several of these topics. • U.S. Health Care in Crisis


Obstentrics_Williams

Obstentrics_Williams. • U.S. Health Care in Crisis In a 2016 issue of the Jounal of the American Medical Association fAA), then-President Barack Obama presented a summary of the Afordable Care Act (ACA), so-called Obamacare. He described the successes, the challenges ahead, and the policy implications of the policy (Bauchner, 2016). He summarized three lessons from his experiences with the ACA. First, change is especially diicult in the face of hyperpartisanship. Second, special interests pose a continued obstacle to change. Third, he stressed the importance of pragmatism. Here, he was referring to the pragmatism necessary when the ACA did not work efectively on day 1 of implementation. TABLE 1-3. Severe Maternal Morbidity Indicators Injuries of thorax, abdomen, and pelvis Intracranial injuries Conversion of cardiac rhythm Hysterectomy Summarized from the Centers for Disease Control and Prevention,l2017b.


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Obstentrics_Williams. Injuries of thorax, abdomen, and pelvis Intracranial injuries Conversion of cardiac rhythm Hysterectomy Summarized from the Centers for Disease Control and Prevention,l2017b. At this same time, draconian cuts to Medicaid were being proposed, and President Obama ended his JM1A report with a quotation from John Kasich, the Republican governor of Ohio. "For those that live in the shadows of life, those who are the least among us, I will not accept the fact that the most vulnerable in our state should be ignored. We can help them." hese potential efects to Medicaid ripple into the specialty of obstetrics. In 2010, it was estimated that Medicaid insured 48 percent of the births in the United States (lvlarkus, 2013). Importantly, Medicaid covered a disproportionate number of complicated births. Speciically, Medicaid insured more than half of all hospital stays for preterm and low-birthweight infants and approximately 45 percent of infant hospital stays due to birth defects.


Obstentrics_Williams

Obstentrics_Williams. he young, healthy Americans who were expected to financially bolster the ACA ultimately enrolled in insuicient numbers to ensure long-term ACA sustainability. hus, long-term options included repair or repeal of the ACA. hroughout Donald Trump's campaign for the presidency of the United States, he made repeal of the ACA a focus of his candidacy. As of this writing, both the United States House of Representatives and the Senate have grappled with "repeal and replace" for 6 months. According to the Congressional Budget Oice, this action would result in 23 million Americans losing health care insurance and cuts in Medicaid dollars (Fiedler, 2017). he latter was to be accomplished by transferring funding of Medicaid from the Federal government to the states.


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Obstentrics_Williams. Overview of Obstetrics 7 hese potential outcomes have prompted considerable debate among voters, and "repeal and replace" has become politically charged. Currently, the Senate has been unable to recruit suficient Republican votes for Senate passage of such a bill. We suggest that the health care crisis should be reframed and redirected instead to a critical analysis of health care costs and resource utilization. that spending on health care in the United States in 2015 accounted for 17.8 percent of the gross domestic product


Obstentrics_Williams

Obstentrics_Williams. that spending on health care in the United States in 2015 accounted for 17.8 percent of the gross domestic product GDP (Voelker, 2010). he total amount of health-care spend ing-$3.2 trillion-equated to an estimated $10,000 per person. Moreover, compared with 12 other high-income coun tries, health-care spending in the United States as a proportion of GDP was approximately 50 percent more than the next highest country. Yet, health-care outcomes, which included infant mortality rates, were worse in the United States. And, approximately two thirds of U.S. infant deaths result from complications stemming from preterm births (Matthews, 2015). Indeed, in its 2010 annual global Premature Birth Report Card, the United States garnered a grade of "D" from the March of Dimes for its recognition and prevention of pre term labor in the more than 540,000 neonates born annually before 37 weeks' gestation.


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Obstentrics_Williams. Causes for the excessive health care costs in the United States are attributed, in part, to greater use of medical technology and excessive prices (Squires, 2017). Two recent studies demonstrate the detrimental efect of obstetrics on health care costs. The first report by Nelson and coworkers (2017) described the inefectiveness of 17 -alpha hydroxyprogesterone caproate (17OHP-C) to prevent recurrent preterm birth. Methodology for this trial is presented in Chapter 42 (p. 817). Several lessons can be learned from this investigation. First, use of 17 -OHP-C was legitimized in the United States by a national consensus committee using expert opinion. hese opinions were promulgated, despite FDA reservations that the evidence was lacking in several important respects. However, once approved, 17 -OHP-C was sold by one pharmaceutical company for $1500 for a single, 250-mg injectable dose. Remarkably, this same dose could be compounded and purchased for $25 from local pharmacies. In the


Obstentrics_Williams

Obstentrics_Williams. 17 -OHP-C was sold by one pharmaceutical company for $1500 for a single, 250-mg injectable dose. Remarkably, this same dose could be compounded and purchased for $25 from local pharmacies. In the subsequent price-gouging controversy, members of the United States Congress intervened to permit continued use of the less expensive 17-0 HP -C.


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Obstentrics_Williams. he second study is a multisite prospective trial of the efectiveness of transvaginal sonography to screen for cervical-length shortening to predict preterm birth (Esplin, 2017). A total of 9410 nulliparous women were studied. he Society for Maternal-Fetal Medicine and the American College of Obstetricians and Gynecologists (2016d) both legitimized universal cervicallength screening in their joint Committee Opinion (Bloom, 2017). And, by 2015, one survey of78 Maternal-Fetal Medicine fellowship programs showed that 68 percent were using universal cervical-length screening to predict preterm birth (Khalifeh, 2017). It was estimated that a modest Medicaid rate of $237 per cervical-length ultrasound would result in approximately $350 million in added health care costs. But, Esplin and associates (2017) found that routine screening for a short cervix was not beneficial. hat is, a widely used intervention was actually inefective. his is a clear example of how unproven technology can seep


Obstentrics_Williams

Obstentrics_Williams. (2017) found that routine screening for a short cervix was not beneficial. hat is, a widely used intervention was actually inefective. his is a clear example of how unproven technology can seep into widespread practice.


Obstentrics_Williams

Obstentrics_Williams. These two reports highlight a substantial problem in U.S. health care, namely, inefective yet expensive interventions introduced into broad use without robust evidence. These two reports also speak to a demand for robust scientific evidence. Scrutiny of other ingredients in the health-care paradigm such as prices for hospitalization, prices for surgical procedures, and prices charged by health insurance companies may illuminate similar contributions to the health care fiscal crisis. In past editions of this textbook, the rising cesarean delivery rate was considered problematic. his rate has leveled, but there are still imperatives in progress to help lower this rate. One collateral source of cesarean delivery morbidity is from the growing incidence of morbidly adherent placentas encountered in women with a prior hysterotomy incision, discussed in Chapters 31 and 41.


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Obstentrics_Williams. Breakthroughs in fetal testing and diagnosis continue to stun. By 2012, prenatal gene micro array techniques were used for clinical management (Dugof, 2012). he advantages of these techniques are outlined in Chapters 13 and 14. Wapner and coworkers (2012) compared chromosomal microarray analysis of maternal blood with karyotyping for chromosomal anomalies. Reddy and associates (2012) applied this technology to stillbirth evaluation and reported it to be superior to karyotyping. Another report by Talkowski and colleagues (2012) described whole-genome sequencing of a fetus using maternal blood.


Obstentrics_Williams

Obstentrics_Williams. Screening for fetal aneuploidy using cell-free DNA (cDNA) was first introduced in 2011. The technique is described in Chapter 14 (p. 284), and it is based on isolation of free fetal (placental) DNA in maternal blood. In a landmark study, Norton and associates (2015) found that cDNA had a higher sensitivity and speciicity compared with standard prenatal screening for trisomy 21 fetuses. Still, invasive testing is currently necessary to confirm a positive cDNA test result (Chitty, 2015; Snyder, 2015).


Obstentrics_Williams

Obstentrics_Williams. • The Ob/Gyn Hospitalist he term "hospitalist" was coined in the 1990s and referred to physicians whose primary professional focus was generalized care of hospitalized patients. From this concept came the obstetrical and gynecological hospitalist whose primary role was to care for hospitalized obstetrical patients and to help manage their emergencies. These physicians could also provide urgent gynecological care and emergency department consultation. Alternative terms include "obstetrical hospitalist" or "laborist," but the preferred standardized term by the American College of Obstetricians and Gynecologists (2016e) is "Ob/Gyn hospitalist." lthough not a recognized subspecialty of obstetrics and gynecology, the Ob/Gyn hospitalist movement has gained momentum. he Society of Ob-Gyn Hospitalists had 528 members in 2017 (Burkard, 2017). Various practice models are described to fit the needs of a wide spectrum of obstetrical volumes (McCue, 2016). In addition to providing lifestyle


Obstentrics_Williams

Obstentrics_Williams. had 528 members in 2017 (Burkard, 2017). Various practice models are described to fit the needs of a wide spectrum of obstetrical volumes (McCue, 2016). In addition to providing lifestyle modifications, Ob/Gyn hospitalists are used by some hospitals to improve the quality and safety of their women's services and to reduce adverse events. Aside from a possible lowering of the labor induction rate, studies are needed to demonstrate improved outcomes with these providers (American College of Obstetricians and Gynecologists, 2016e; Srinivas, 2016).


Obstentrics_Williams

Obstentrics_Williams. he American College of Obstetricians and Gynecologists periodically surveys its fellows concerning the efect of liability on their practice. he 2015 Survey on Professional Liability is the 12th such report since 1983 (Carpentieri, 2015). From this survey, it appears that there is still a "liability crisis," and the reasons for it are complex. Because it is largely driven by money and politics, a consensus seems unlikely. Although some interests are diametrically opposite, other factors contribute to the problem's complexity. For example, each state has its own laws and opinions on tort reform. In some states, annual premiums for obstetricians approach $300,000-expenses that at least partially are borne by the patient and certainly by the entire health-care system. In 2011, all tort costs in the United States totaled nearly $265 billion. his is an astounding 1.8 percent of the gross domestic product and averages to a cost of $838 per citizen (Towers Watson, 2015).


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Obstentrics_Williams. he American College of Obstetricians and Gynecologists (2016a,c) has taken a lead in adopting a fair system for malpractice litigation-or maloccurrence itigation. And nationally, there is the possibility of federl tort reform under the Trump administration (Lockwood, 2017; Mello, 2017). Following a slight decline from 1990 through 2004, the percentage of out-of-hospital births in the United States increased from 0.86 to 1.5 percent-almost 75 percent-through 2014 (MacDorman, 2016a). Of these home births, only a third are attended by nurse midwives certiied by the American Midwife Certiication Board (Grtinebaum, 2015; Snowden, 2015).


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Obstentrics_Williams. Proponents of home births cite successes derived from laudatory observational data from England and he Netherlands (de Jonge, 2015; Van der Kooy, 2011). Data from the United States, however, are less convincing and indicate a higher incidence of perinatal morbidity and mortality (Grtinebaum, 2014, 2015; Snowden, 2015; Wasden, 2014; Wax, 2010). hese latter findings have led Chervenak and coworkers (2013, 2015) to question the ethics of participation in planned home births. Greene and Ecker (2015) take a broader view. Given data from these more recently cited studies, they are of the view that these data empower women to make a rational decision regarding home delivery. he American College of Obstetricians and Gynecologists (20 17b) believes that hospitals and accredited birth centers ofer the safest settings, but that each woman has the right to make a medically informed decision regarding delivery.


Obstentrics_Williams

Obstentrics_Williams. Politics and religion over the years have led to various govern mental interferences with the reproductive rights of women. adolescents. This is despite all reports of the overwhelming suc cess of such programs. One example is the exclusion of Planned Parenthood ailiates from the Texas Medicaid fee-for-service family planning program. In some groups of women served, there was discontinuation of contraception and an increased rate of Medicaid binhs (Stevenson, 2016),


Obstentrics_Williams

Obstentrics_Williams. According to the Gurrmacher Institute (2016a), publicly funded family planning services are needed by 20 million American women. In 2014, such services prevenred nearly 2 million unintended pregnancies and 700,000 abonions in the United States. The fate of family planning services is not fully determined, while waiting for decisions regarding provisions within the 2017 American Healrh Care Ace (AHCA). or "Trumpcare." In his response ro news that the AHCA may dismantle cOlHraceptive coverage, American College of Obstetricians and Gynecologises President Dt. Haywood Brown (2017) called this a deep disregard for women's health.


Obstentrics_Williams

Obstentrics_Williams. According to the CDC (2014). there were 259 million prescriptions written in 2012 for opioid medications. In 2013, more than a rhird of American adults reported prescrip tion opioid use (Han, 2017). These fteely available-albeit requiring a prescription-addictive drugs are associated with opioid use disorders. It remains uncercain if opioid use is terarogenic (Lind, 2017). Still, their abuse by pregnam women has caused an unprecedented rise in the 1eonata/ abstinence syndrome. described furrher in Chapters 12 (p. 248) and 33 (p. 625). Treatment of opioid abuse in pregnancy and its sequelae result in $1.5 billion annually in hospital charges.


Obstentrics_Williams

Obstentrics_Williams. For obstetrical providers ro bener deal with opioid-addicted pregnant women and their fetus-newborns, the Eu.nice Kennedy Shriver National Institute of Child Helth and Human Development convened a workshop in 2016 co study many aspecrs of the problem (Reddy. 2017). he Workshop was cosponsored by the American College of Obstetricians and Gynecologisrs, the American Academy of Pediatrics, the Society for Maternal-Fetal Medicine, the CDC, and the March of Dimes. Several copies were addressed, and hopefully implementation of these indings will help improve maternal treatment and neonatal outcomes (American College of Obstetricians and Gynecologists. 2017a).


Obstentrics_Williams

Obstentrics_Williams. The bold new concept of in-vitro fercilization (IVF) produced the irst IVF baby in Britain in 1978. This was soon followed in 1981 with an American success. After four decades. the Society for Assisted Reproductive Technology (SART) reports that more than 1 million babies have been born in the United States using assisted reproductive technologies (ART) ofered by 440 clinics (Fox. 2017). ter IS years of experimental preparation. the promise of a successful human uterine transplant was finally realized with n Overview of Obstetrics 9 IVF-conceived livebon neonate in Sweden (Brinnstrom, 2015).


Obstentrics_Williams

Obstentrics_Williams. Overview of Obstetrics 9 IVF-conceived livebon neonate in Sweden (Brinnstrom, 2015). During pregnancy, the mother was treated with t:lcrolimus, azathioprine, and corticosteroids and underwent cesarean delivery at 32 weeks for preeclampsia and abnormal feral heart rate testing. This was followed by uterine trmsplamation programs at the C1cvebnd Clinic and Baylor Medical Center in Dallas (F1yckt. 2016. 2017, Testa. 2017). In 2017. the Swedish team had completed a nine-patient trial, in which seven women had become pregnant and ive had sllccessful deliveries (Kuehn, 2017). Also, in Dallas, the irst such newbon in the Unired Stares was born (Rice. 2017).


Obstentrics_Williams

Obstentrics_Williams. Meanwhile, researchers at Children's Hospital of Philadelphia pursued a 20-year goal in search of an artiicial womb (Yuko, 2017). Using incubatOr technology, [he team devised an artiicial amnionic sac. hrough this, (he umbilical vessels were perfused and drained, and the blood was retuned to systems [hat performed exrracorporeal membrane oxygenation and dialysis. To date, lamb fetuses have been kept alive for as long as 1 month. Adverse efects of cerebrovascular hypotension and hypoxemia are conjectural but highly worrisome. 1he ethical and legal challenges of these new technologies are daunting. Of those that arose from IVF, mOSt are setded. For the Q[her twO endeavors, there are likely many years of ethical and legal milestones ahead. American Academy of Pediatrics, American College of Obstetricians and Gynecologisrs: Guidelines for perinatal care, 8th ed. Elk Grove Village, AAP,e2017


Obstentrics_Williams

Obstentrics_Williams. American Academy of Pediatrics, American College of Obstetricians and Gynecologisrs: Guidelines for perinatal care, 8th ed. Elk Grove Village, AAP,e2017 American College of Obstetricians and Gynecologists: Coping with the stress or medical profeSSional liabiliry litigation. Committee Opinion No. 551, January 2013, Reairmed 2016a American College of Obm=tricians and Gynecologists: Deinition of term pregnancy. Comminee Opinion No. 579, November 2013, Reairmed 2016b American College of Obstetricians and Gyneologists: Disclosure and discussion of adverse events. Committee Opinion No. 681, December 2016c American College of Obstetricians and Gynecologists: Prediction and prevention of preterm birth. Practice Bulletin No. 130, October 2012, Reairmed 2016d American College of Obstetricians and GynecologiSts: The obstetric and ynecologic hospitalist. Committee Opinion No. 65-, February 2016e


Obstentrics_Williams

Obstentrics_Williams. American College of Obstetricians and GynecologiSts: The obstetric and ynecologic hospitalist. Committee Opinion No. 65-, February 2016e American College of Obstetricians and Gynecologists: Opioid use and opioid use disorder in pregnancy. Committtt Opinion No. 711, August 2017a American College of Obstetrics and Gynecologists: Planned home birth. Com mittee Opinion No. 697, April 2017b American College of Obstetricians and Gynecologists; Society for MaternalFetal Medicine: Severe maternal morbidity: screening and review. Obstetric Care Consensus No.e5, Seprember 201M Barbieri L: Reducing maternal mortality in the United States-let's get organized! OBG Manag 27(9):8, 2015 Bauchner H: The Afordable Care Act and the fmure of US health care. JA 316(SH92.e2016 Berg q, Callaghan WM, Syverson C, er al: Pregnany-relared mortality in the United States, 1998 TO 2005. Obsret Gynecol 116: 1302, 20 I0


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Obstentrics_Williams. Berg q, Callaghan WM, Syverson C, er al: Pregnany-relared mortality in the United States, 1998 TO 2005. Obsret Gynecol 116: 1302, 20 I0 Berg q, Harper MA, Atkinson SM, er al: Preventability of pregnancy-related deaths. Results of a state-wide review. Obstet Gynecol 106; 1228, 2005 Bloom SL, Leveno KJ: Unproven rechnologies in marernal-feral medicine and the high COSt of US health care. JNvlA 317(10):1025, 2017 Brannstrom M, Johannesson L, Bokstrom H, er al: Uvebinh after uterus transplantation. Lancet 385(9968):2352, 2015 Brown HL: We're seeing a deep disregard for women's health. ACOG Government Afairs, June 7, 2017 Burkhard J; Personal communication. May 2017 Callaghan M, Creanga M, Kuklina EV: Severe maternal morbidity among delivery and postpartum hospitalizatiOns in the United Stares. Obsrer Gyne001 120(S),1029. 2012


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Obstentrics_Williams. Callaghan M, Creanga M, Kuklina EV: Severe maternal morbidity among delivery and postpartum hospitalizatiOns in the United Stares. Obsrer Gyne001 120(S),1029. 2012 Carpentieri A\1, Lumalcuri JJ, Sh;l\\I J. e( al: Oveview of the 2015 American Congress of QhslNrics and Gynecologists survey on professional liability. Clinical Review 20: I, 20n15 Centers for Disease Conrrol and Prevention: National Center for Health Statistics: Fetal death. 2016. Available at: hnps:ll".cdc.gov/nchs/nvssl fec\l_dearh.hun. Acccs�cd Scptcmbu 6, 2017 Centers for Disease Control and Prevention: Pregnancy mortality surveillance system. 20 17a. Available at: https:I/\ww.cdc.govlrcprodllctivehealth/ matenalinfanthcalth/pmss.html. Accessed September 6.n2017 Centers for Disease Control and Prevention: Severe maternal morbidity in the United Slates. 2017b. Available at: hnps:/Iw.cdc.govlreproductivchealthfmarenalinfanrhealrh/scveremarcrnalmorbidiry.huul. Accessed Seprcmbern6,n2017


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Obstentrics_Williams. Ccnters for Disease Comrol and Prcvcntion: Vital signs: opioid painkillcr prescribing. 2014. Available at: Ilttps:llww.cdc.gov/vitalsigns/opioid-prescribinglindex.luml. Accessed September 6, 2017 Chervenak FA, Gruncbaunl A: Home birth: the ohsterrician's ethical response. COlltemp Ob/Gyn May 8, 2015 Chervenak FA, .1cCullough LB, Brent RL, et al: Planned horne birth: (he professional responsibiliry response. Am J Ohs(e( G'necol 208(1 ):31. 2013 Chescheir NC: Enough already! Obstet GynecoIn12S(l):2, 2015 Chitty LS: Use of cell-f..-e DNA to screen for Down's syndrome. N Engl J Med 372(17),1666, 2015 Clark SL, Belforr \A, Dildy GA, et al: Maternal death in the 21st century: causes, prevcntion, and relationship to cesarean delivery. Am J Obstet Gynecol 199(1 ):36.cl, 2008


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Obstentrics_Williams. Clark SL, Belforr \A, Dildy GA, et al: Maternal death in the 21st century: causes, prevcntion, and relationship to cesarean delivery. Am J Obstet Gynecol 199(1 ):36.cl, 2008 Clark SL, Meyers JA. Frye DR, et 11: A sysrematic approach to the identiication and classiication of near-miss cvems on lahor and delivery in a largc, national health care systcm. Am J Obstet Gynecol 207(5):441, 2012 Creanga A, Bateman BT, KukJina EV, e{ al: Racial and ethnic disparities in sevcre maternal morbidiry: a multisrate analysis, 2008-2010. Amn) Obsret Gynccol 21O(5):435.e1, 2014 Creanga A, Berg q, Syverson C, ct al: Pregnancy-related mortality in the United States, 2006-20 I O. Obstct Gynecol 125:5. 20n15 Creanga A, Syverson C, Seed K et al: Pregnancy-related mortality in the United States, 201n1-2013. Obstet GynecoIn130(2):366, 2017


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Obstentrics_Williams. Creanga A, Syverson C, Seed K et al: Pregnancy-related mortality in the United States, 201n1-2013. Obstet GynecoIn130(2):366, 2017 D'AltOn rvlE, Friedman M. Smiley RM, et l: Nation:ll partnership for maternal safety: consensus bundle on venous thromboembolism. Obstet Gynecol 128,688-98, 2016 de Jonge A, GeertS CC. van der Goes BY, et al: Perinatal mortality and morbidity up fO 28 days after birth among 743,070 low-risk planned home and hospiral births: a cohort study based on three merged national pcrinaral d:uabase. BJOG 122(5):720,n2015 Dugof L: Application of genomic technology in prenatal diagnosis. N Engl J M,d 367(23),2249, 2012 Esplin MS, Eloviu MA, lams JD, '1al: Predicrivc accuracy of serial transvaginal cervicalnlengrhs and quantitative vaginal fetal flbroncctin levels of spontaneous preterm birth among nulliparous women. JAh-IA 317( 1 0): 1047,n2017


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Obstentrics_Williams. Fiedler M, Aaron HJ, Adler L, et al: Moving in the wrong direction-health care under the AHCA. N Engl J Med 376(25):2405, 2017 Flyckr R, Kodyar A, Arian S, er al: Deceased donor uterine transplantation. Ferril Steril I07(3):eI3, 2017 Flyckr L, Farrell M, Peni US, et al: Deceased donor uterine transplantation: innovation and adaptation. Obstet GynecoIn128(4):837, 2016 Fox M: A million babies have been born in the U.S. wirh fertiliry help. Helth NBC News, April 28, 201i Frey WH: America reaches i('s ([cmographic tipping poinr. 201n1. Available at: h t t ps:!1www.brooki ngs.cdu/blng/up-fronr/20 11/08/261 america -reaches-i rsdemographic-tipping-point.! Accessed September 6, 2017 Grttne MF, Ecker JL: ChOOSing beneits while balanCing risks. N Engl J t\lcd 373(27),2681,n2015


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Obstentrics_Williams. Grttne MF, Ecker JL: ChOOSing beneits while balanCing risks. N Engl J t\lcd 373(27),2681,n2015 Gri.inebaum A, .lcCullough LB, Brelll L, e{ : Perinatal risks of planned home binhs in the United States. Am J Obstet Gynecol 212(3):350, 2015 Grunebaum A, Sapra K, Chervenak F: Term neonatal deaths resulting from hone births: an increasing trend. m J Obstet Gynecol 21O:S57, 2014 Guttmacher Institute: Fact sheer: publicly funded family planning services in [he United States. 2016a. Available at: https:II\Vw.gurtmacheLorgilct -sheet!publ idy-fu nded-fa IIi 1),-plann i ng-services-u n i ted -5ta res. Accessed September 6, 2017 Guttmacher Institute: Fact sheet: uninrended pregnancy in the United States. 2016b. A\<ailable at: lmps:llwww.gunmacher.orglact-shcct/uninrendedpregnancy-unired-states. AccCSL-d September 6, 2017 Hamilton BE, Marrin JA, OSlerman MJ, et al: Birrhs: inal dara for 2014. Natl Vital Stat Rep 54:\, 2015


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Obstentrics_Williams. Hamilton BE, Marrin JA, OSlerman MJ, et al: Birrhs: inal dara for 2014. Natl Vital Stat Rep 54:\, 2015 Hamilton BE, Marrin JA, Ventura 5): Births: preliminary data for 2011. Nad Vital S[3( Rep 61 (5): I, 2012 Han B, Compton W.1. Blanco C, et l: Prescription opioid usc, misuse, and use disorders in U.S. adults: 2015 National Survey on Drug Use and Healrh. Ann Imern \led 167(5):293,n2017 Hehir \lP, Ananth CV, Wright JD, er al: Severe matenal morbidity and comorbid risk in hospitals performing <1000 deliveries per year. m J Obstct GynecoI 21G(2):179.el, 2017 Heron M: Deaths: leading causes for 2011. Nad Vital Srat Rep 64(7): 1, 2015 Howell A, Egorova NN, Balbierz A, e( al: Site of delivery contribution to black-white severe matenal morbidity disparity. 215(2):143, 2016 Hoyen DL: Maternal mortality and related concepts. Vital Health Stat 3(33), I, 2007


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Obstentrics_Williams. Hoyen DL: Maternal mortality and related concepts. Vital Health Stat 3(33), I, 2007 Institute for Safe �ledication Practices: ISMP survey helps deine near miss and de call. Medication Safety Alert, September 24, 2009. Available at: hn ps:ll\vww.ismp.orgl newsletters} acure.lfelanidesl20090n4 .asp. Accessed September 6,n2017 Joseph KS, Lisonkova S, Muraca GM, et al: Factors underlying the temporal increase in maternal mortaliry in the United States. 129{I ):91, 2017 KJlalifch A, Quist-Nelson ), Berghella V: Universal cervical lengTh screening for pretcnn birth prevention in the United States. J Maten Feral Neonatal Moo 30,1n500, 2017 King JC: Maternal mortality in Ihe United States-why is il imporrant and what are we doing about it? Semin PerinatoIn36(1):14, 2012 Knight M, Kurincwk JJ, Tufnell D, el al: 111e UK obstetric surveillance system for rare disorders of pregnancy. BJOG 112:263. 2005


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Obstentrics_Williams. Knight M, Kurincwk JJ, Tufnell D, el al: 111e UK obstetric surveillance system for rare disorders of pregnancy. BJOG 112:263. 2005 Knight M, UKOSS: Antenatal pulmonary embolism: risk f..clOrs, management and outcomes. B)OG 11n5:453,n2008 Koonin LM, MacKay AP, Berg q, et al: Pregnancy-related morrality surveillance-United States, 1987-1990. MMWR 46(4):17,n1997 Kuehn I�M: US uterus transplant (fials under way. JAM A 317( I0): I 005,n2017 Lind )N, Interranre )D, Ailes EC, et al: Matenal usc of opioids during pregnancy and congeniral malformations: a systematic review. Pediatrics 139(6),,20164131,n201 Lockwood CJ: Is federal mOicalnliabiliry reform possible? COlHcmp OB/GYN July 2017 MacDorman MF, Declercq E: Trends and charactcristics of United States outof-hospital births 2004-20n14: new information on risk staws and access to carc. Birth 43(2): 1 16, 2016a


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Obstentrics_Williams. MacDorman MF, Declercq E: Trends and charactcristics of United States outof-hospital births 2004-20n14: new information on risk staws and access to carc. Birth 43(2): 1 16, 2016a MacDonnan "-IF, Declercq E, Cabral H, et ;\1: Recent increases in the U.S. maternal mortality rate: disentangling trends from measuremem issues. Obstet GynecoIn128(3):447, 2016b �lacDorman MF, Declercq E, 1110ma ME: Trends in matenal mortality by sociodcmographic characteristics and cause of death in 27 states and the Dimi" of Columbia. Obstet Gynccol 129(5):811,n2017 MacDorman MF, Gregory EC: Fe!'al and perinatal mortality: United States, 2013. Nat! Vital Star R:p 64(8): 1, 2015 Main EK, Cape V, Abreo A, et al: Reduction of severe matcnal morbidity from hemorrhage using a state perinatal qualiry collaborative. Am J Obstet Gynccol 216(3):298.el, 2017


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Obstentrics_Williams. Main EK, Cape V, Abreo A, et al: Reduction of severe matcnal morbidity from hemorrhage using a state perinatal qualiry collaborative. Am J Obstet Gynccol 216(3):298.el, 2017 Main EK, Coffman D, Scavone B� I,et al: National partnership for materna! safety: consensus bundle on obstetric hemorrhage. Obstet Gynreol 126( I); 155, 2015 �Iarkus AR, Andres E, West D, et Il: Medicaid covered births, 2008 through 2010, in rhe concexr of the implementation of health reform. Womens Health Issues 23(5):e273. 2013 �1aron DF: 1.laternal health care is disappearing in rural America. Scientiic American, February 15,n2017 Martin JA, Hamilton BE, Osterman MJK, et al: Births: inal data for 2015. National Vital Statistics Report 66: 1, 2017


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Obstentrics_Williams. Martin JA, Hamilton BE, Osterman MJK, et al: Births: inal data for 2015. National Vital Statistics Report 66: 1, 2017 Matthews RJ, MaeDorman MF, Thoma ME: In.1l1t mortality s:uistis from the 2013 period linked birth/in..lJl( death data set. Nat! Vital Stat Rep 64(9): 1,2015 t\IcCue B, Fagnant R, Townsend A, et al: Deinitions of obstetric and ynecologic hospitalists. Qbstel GynecoIn127(2):393, 2016 �Iello MM, Kachalia A, Sruddert D\I: Medicalnliabiliry�prospeclS for federal reform. N Engl J �Ied r6(19):1806, 2017 �loaddab A, Dildy GA, Brown H L, et al: Health care disparity and state-speciic pregnancy-related mortality in the United States, 2005-2014. Obstet Gynccol 128:869,n2016 Nelson DB, Mcintire DO, McDonald J, et al: 17-Alpha hydroxyprogestetone caprOate did not reduce the ratc of recurrent prcterm birth in a prospective cohort study. Am J Obstet Gynecol 216:600.e 1, 2017


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Obstentrics_Williams. NortOn ME. Jacobsson B, Swamy GK, et al: Cell-free DNA analysis for noninvasive examination of trisomy. N Engl J Moo 373(26):2582, 2015 Reddy UM, Davis )M, Ren Z, e1al: Opioid cin pregnancy, neonatal abstinence syndrome, and childhood Outcomes. Obsret Gynecol 130(1): 10. 201 Reddy UM, Page GP, Saade GR, et al: Karyotype versus microarra), testing for generic abnormalities after stillbirth. N Engl) Med 367(23):2185, 2012 Rice S: Baylor doctors deliver irst baby born in U.S. after uterine transplant. Dallas i\lorning News. December 2, 2017 Shields LE, Wiesner S, Klein C, et al: Early standardized treatment of critical blood pressure elevations is associated with a reduction in eclampsia and severe maternal morbidity. Am J Obstet GynecoI216(4):415.el, 2017 Snowden JM, Tilden EL, Snyder J, et al: Planned out-of-hospital birth and birth outcomes. N Engl J Med 373:2642,r2015


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Obstentrics_Williams. Snowden JM, Tilden EL, Snyder J, et al: Planned out-of-hospital birth and birth outcomes. N Engl J Med 373:2642,r2015 Snyder M, Simmons LE, Kitzman JO, et al: Copy-number variation and false positive prenatal aneuploidy screening results. N Engl J Med 372(1 ): 1639, 2015 Souza JP, Cecatti JG, Haddad SM, et al: he WHO maternal near-miss approach and the maternal severity index model (MSI): tools for assessing the management of severe maternal morbidity. PLoS One 7(8):e44129, 2012 Squires 0, Anderson C: US health care from a global perspective, spending, use of services, prices, and health in ] 3 countries. Issue Brief (Commonw Fund) 15:1,r2015 Srinivas SK, Small OS, Macheras M, et al: Evaluating the impact of the laborist model of obstetric care on maternal and neonatal outcomes. Am J Obstet GynecoIr215:770.el,r2016 Stevenson AJ, Flores-Vazquez 1M, Allgeyer RL, et al: Efect of removal of Planned Parenthood from the Texas women's health program. N Engl J Med 374(9):853, 2016


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Obstentrics_Williams. Stevenson AJ, Flores-Vazquez 1M, Allgeyer RL, et al: Efect of removal of Planned Parenthood from the Texas women's health program. N Engl J Med 374(9):853, 2016 Overview of Obstetrics 11 Talkowski ME, Ordulu Z, Pillalamarri V, et al: Clinical diagnosis by wholegenome sequencing of a prenatal sample. N EnglJ Med 367(23):2226, 2012 Tavenise S: Maternal mortality rate in U.S. rises, deying global trend, study finds. New York Times, September 21,r2016 Testa G, Koon EC, Johannesson L, et al: Living donor uterus transplantation: a single center's observations and lessons leaned from early setbacks to technical success. Am J Transplant, April 22, 2017 [Epub ahead of print] Towers Watson: Update of U.S. tort cost trends. Available at: towerswatson. com. Accessed July 30,r201


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Obstentrics_Williams. Towers Watson: Update of U.S. tort cost trends. Available at: towerswatson. com. Accessed July 30,r201 Yan der Kooy J, Poeran J, de Graaf JP, et l: Planned home compared with planned hospital births in the Netherlands. Obstet Gynecol 118(5): 1037, 2011 Yoelker R: US preterm births: "0" is for dismal. JAMA 303(2):116,r2010 Wapner RJ, Martin CL, Levy B, et al: Chromosomal microarray versus karyo typing for prenatal diagnosing. N Engl J Med 367(23):2175, 2012 Wasden S, Perlman J, Chasen S, et al: Home birth and risk of neonatal hypoxic ischemic encephalopathy. Am J Obstet Gynecol 21 0:S251, 2014 Wax JR, Lucas FJ, Lamont M, et al: Maternal and newbon oLltcomes in planned home birth vs planned hospital births: a metaanalysis. Am J Obstet GynecoIr203(3):243,r2010 Yuko E: Weighing the ethics of artiicial wombs. New York Times, May 8,r2017 ANTERIOR ABDOMINAL WALL . . . . . . . . . . . . . . . . . . . . . 14 EXTERNAL GENERATIVE ORGANS ... .... .. 16


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Obstentrics_Williams. Yuko E: Weighing the ethics of artiicial wombs. New York Times, May 8,r2017 ANTERIOR ABDOMINAL WALL . . . . . . . . . . . . . . . . . . . . . 14 EXTERNAL GENERATIVE ORGANS ... .... .. 16 INTERNAL GENERATIVE ORGANS .......... ..... . 23 LOWER URINARY TRACT STRUCTURES ... . 28 MUSCULOSKELETAL PELVIC ANATOMY . .. 29 As the mechanism of labour is essentialy a process of accommodation between the oetus and the passage through which it must pass, it is apparent that obstetrics lacked a scientiic oundation until the anatomy of the bony pelvis and of the sot parts connected with it was cleary understood -J. Whitridge Williams (1903) • Skin, Subcutaneous Layer, and Fascia he anterior abdominal wall confines abdominal viscera, stretches to accommodate the expanding uterus, and provides surgical access to the internal reproductive organs. hus, a comprehensive knowledge of its layered structure is required to surgically enter the peritoneal cavity.


Obstentrics_Williams

Obstentrics_Williams. Langer lines describe the orientation of dermal fibers within the skin. In the anterior abdominal wall, they are arranged transversely. As a result, vertical skin incisions sustain greater lateral tension and thus, in general, develop wider scars. In contrast, low transverse incisions, such as the Pfannenstiel, follow Langer lines and lead to superior cosmetic results. The subcutaneous layer can be separated into a superficial, predominantly fatty layer-Camper fascia, and a deeper membranous layer-Scarpa fascia. Camper fascia continues onto the perineum to provide fatty substance to the mons pubis and labia majora and then to blend with the fat of the ischioanal fossa. Scarpa fascia continues inferiorly onto the perineum as Colles fascia, described on page 19.


Obstentrics_Williams

Obstentrics_Williams. Beneath the subcutaneous layer, the anterior abdominal wall muscles consist of the midline rectus abdominis and pyramidalis muscles as well as the external oblique, internal oblique, and transversus abdominis muscles, which extend across the entire wall (Fig. The ibrous aponeuroses of these three latter muscles form the primary fascia of the anterior abdominal wall. These fuse in the midline at the linea alba, which normally measures 10 to 15 mm wide below the umbilicus (Beer, 2009). n abnormally wide separation may reflect diastasis recti or hernia.


Obstentrics_Williams

Obstentrics_Williams. These three aponeuroses also invest the rectus abdominis muscle as the rectus sheath. The construction of this sheath varies above and below a boundary, termed the arcuate line (see Fig. 2-1). Cephalad to this border, the aponeuroses invest the rectus abdominis bellies on both dorsal and ventral surfaces. Caudal to this line, all aponeuroses lie ventral or supericial to the rectus abdominis muscle, and only the thin transversalis fascia and peritoneum lie beneath the rectus (Loukas, 2008). This transition of rectus sheath composition can be seen best in the upper third of a midline vertical abdominal incision. he paired small triangular pyramidalis muscles originate from the pubic crest and insert into the linea alba. These muscles lie atop the rectus abdominis muscle but beneath the anterior rectus sheath.


Obstentrics_Williams

Obstentrics_Williams. he supericial epigastric, supericial circumlex iliac, and supericial external pudendal arteries arise from the femoral artery just below the inguinal ligament within the femoral triangle Rectus abdominis m. External oblique m. Internal oblique m. Transversus abdominis m. Lateral cutaneous n. Genital branch of genitofemoral n. Internal thoracic a. Superior epigastric a. Inferior epigastric a. Superficial circumflex iliac a. External pudendal a. with emerging round ligament, ilioinguinal & genitofemoral nn.


Obstentrics_Williams

Obstentrics_Williams. Internal thoracic a. Superior epigastric a. Inferior epigastric a. Superficial circumflex iliac a. External pudendal a. with emerging round ligament, ilioinguinal & genitofemoral nn. FIGURE 2-1 Anterior abdominal wall anatomy. (Modified with permission from Corton MM: Anatomy. In Hoffman BL, Schorge JO, Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 2016) (see Fig. 2-0. These vessels supply the skin and subcutaneous layers of the anterior abdominal wall and mons pubis. Of these three, the superficial epigastric vessels are surgically important to the obstetrician and course diagonally from their origin toward the umbilicus. With a low transverse skin incision, these vessels can usually be identified at a depth halway between the skin and the anterior rectus sheath. They lie above Scarpa fascia and several centimeters from the midline. Ideally, these vessels are identiied and surgically occluded.


Obstentrics_Williams

Obstentrics_Williams. In contrast, the inferior "deep" epigastric vessels are branches of the external iliac vessels and supply anterior abdominal wall muscles and fascia. Of surgical relevance, the inferior epigastric vessels initially course lateral to, then posterior to the rectus abdominis muscles, which they supply. Above the arcuate line, these vessels course ventral to the posterior rectus sheath and lie between this sheath and the posterior surface of the rectus muscles. Near the umbilicus, the inferior epigastric vessels anastomose with the superior epigastric artery and vein, which are branches of the internal thoracic vessels. Clinically, when a Maylard incision is used for cesarean delivery, the inferior epigastric vessels may be lacerated lateral to the rectus belly during muscle transection. Preventively, identiication and surgical occlusion are preferable. These vessels rarely may rupture following abdominal trauma and create a rectus sheath hematoma (Toicher, 2010; Wai, 2015).


Obstentrics_Williams

Obstentrics_Williams. On each side of the lower anterior abdominal wall, Hesselbach triangle is the region bounded laterally by the inferior epigastric vessels, inferiorly by the inguinal ligament, and medially by the lateral border of the rectus abdominis muscle. Hernias that protrude through the abdominal wall in Hesselbach triangle are termed direct inguinal hernias. In contrast, indirect inguinal hernias do so through the deep inguinal ring, which lies lateral to this triangle, and then may exit out the supericial inguinal ring. he entire anterior abdominal wall is innervated by intercostal nerves (T 7-"i )ithe subcostal nerve (T'2)•' and the ilio hypogastric and the ilioinguinal nerves (L,). Of these, the Intecostal n. Internaloblique m. External __.oblique m. Lateral Anterior ramus


Obstentrics_Williams

Obstentrics_Williams. FIGURE 2-2 Intercostal and subcostal nerves are the anterior rami of spinal nerves. In this figure, an intercostal nerve extends ventrally between the transversus abdominis and internal oblique muscles. During this path, the nerve gives rise to lateral and anterior cutaneous branches, which innervate the anterior abdominal wall. As shown by the inserted needle, the transversus abdominis plane (TAP) block takes advantage of this anatomy. (Modified with permission from Hawkins JL: Anesthesia for the pregnant woman. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al: Cunningham and Gilstraps's Operative Obstetrics, 3rd ed. New York, McGraw Hill Education, 201o7.) intercostal and subcostal nerves are anterior rami of the thoracic spinal nerves and run along the lateral and then anterior abdominal wall between the transversus abdominis and internal oblique muscles (Fig. 2-2). his space, termed the transversus abdominis plane, can be used for postcesarean analgesia blockade (Chap. 25, p.


Obstentrics_Williams

Obstentrics_Williams. wall between the transversus abdominis and internal oblique muscles (Fig. 2-2). his space, termed the transversus abdominis plane, can be used for postcesarean analgesia blockade (Chap. 25, p. 500) (Fusco, 2015; Tawfik, 2017). Others report rectus sheath or ilioinguinaliliohypogastric nerve blocks to decrease postoperative pain (Mei, 2011; Wolfson, 2012).


Obstentrics_Williams

Obstentrics_Williams. Near the rectus abdominis lateral borders, anterior branches of the intercostal and subcostal nerves pierce the posterior sheath, rectus muscle, and then anterior sheath to reach the skin. hus, these nerve branches may be severed during a Pfannenstiel incision creation during the step in which the overlying anterior rectus sheath is separated from the rectus abdominis muscle.


Obstentrics_Williams

Obstentrics_Williams. In contrast, the iliohypogastric and ilioinguinal nerves originate from the anterior ramus of the first lumbar spinal nerve. They emerge lateral to the psoas muscle and travel retroperitoneally across the quadratus lumborum inferomedially toward the iliac crest. Near this crest, both nerves pierce the transversus abdominis muscle and course ventromedially. At a site 2 to 3 cm medial to the anterior superior iliac spine, the nerves then pierce the internal oblique muscle and course supericial to it toward the midline (Whiteside, 2003). The iliohypogastric nerve perforates the external oblique aponeurosis near the lateral rectus border to provide sensation to the skin over the suprapubic area (see Fig. 2-1). The ilioinguinal nerve in its course medially travels through the inguinal canal and exits through the supericial inguinal ring, which forms by splitting of external abdominal oblique aponeurosis fibers. This nerve supplies the skin of the mons pubis, upper labia majora, and medial


Obstentrics_Williams

Obstentrics_Williams. exits through the supericial inguinal ring, which forms by splitting of external abdominal oblique aponeurosis fibers. This nerve supplies the skin of the mons pubis, upper labia majora, and medial upper thigh.


Obstentrics_Williams

Obstentrics_Williams. The ilioinguinal and iliohypogastric nerves can be severed during a low transverse incision or entrapped during closure, especially if incisions extend beyond the lateral borders of the rectus abdominis muscle (Rahn, 2010). These nerves carry sensory information only, and injury leads to loss of sensation within the areas supplied. Rarely, chronic pain may develop (Whiteside, 2005). he T 10 dermatome approximates the level of the umbilicus. Analgesia to this level is suitable for labor and vaginal birth. Regional analgesia for cesarean delivery or for puerperal sterilization ideally extends to T4' Mons Pubis, Labia, and Clitoris


Obstentrics_Williams

Obstentrics_Williams. Mons Pubis, Labia, and Clitoris The pudenda-commonly designated the vulva-includes all structures visible externally from the symphysis pubis to the perineal body. This includes the mons pubis, labia majora and minora, clitoris, hymen, vestibule, urethral opening, greater vestibular or Bartholin glands, minor vestibular glands, and paraurethral glands (Fig. 2-3). he vulva receives innervations and vascular support from the pudendal nerve (p. 22). he mons pubis is a fat-illed cushion overlying the symphysis pubis. After puberty, the mons pubis skin is covered by curly hair that forms the triangular escutcheon, whose base aligns with the upper margin of the symphysis pubis. In men and some hirsute women, the escutcheon extends farther onto the anterior abdominal wall toward the umbilicus.


Obstentrics_Williams

Obstentrics_Williams. Labia majora usually are 7 to 8 cm long, 2 to 3 cm wide, and 1 to 1.5 cm thick. They are continuous directly with the mons pubis superiorly, and the round ligaments terminate at their upper borders. Hair covers the labia majora, and apocrine, eccrine, and sebaceous glands are abundant. Beneath the skin, a dense connective tissue layer is nearly void of muscular elements but is rich in elastic fibers and fat. his fat mass provides bulk to the labia majora and is supplied with a rich venous plexus. During pregnancy, this vasculature may develop varicosities, especially in multiparas, from increased venous pressure created by the enlarging uterus. hey appear as engorged tortuous veins or as small grapelike clusters, but they are typically asymptomatic and require no treatment.


Obstentrics_Williams

Obstentrics_Williams. Each labium minus is a thin tissue fold that lies medial to each labium majus. he labia minora extend superiorly, where each divides into two lamellae. From each side, the lower lamellae fuse to form the frenulum of the clitoris, and the upper lamellae merge to form the prepuce (see Fig. 2-3). Inferiorly, the labia minora extend to approach the midline as low ridges of tissue that join to form the fourchette. The labia minora dimensions vary greatly among individuals, with lengths from 2 to 10 cm and widths from 1 to 5 cm (Lloyd, 2005). Structurally, the labia minora are composed of connective tissue with numerous vessels, elastin ibers, and very few smooth muscle ibers. hey are supplied with many nerve endings and are extremely sensitive (Ginger, 20i1i1a; Schober, 2015). The epithelia of the labia minora difer with location. Thinly keratinized stratiied squamous epithelium covers the Glans of clitoris Inferior fascia of levator ani mm./ External anal sphincter m.


Obstentrics_Williams

Obstentrics_Williams. Glans of clitoris Inferior fascia of levator ani mm./ External anal sphincter m. FIGURE 2-3 Vulvar structures and subcutaneous layer of the anterior perineal triangle. Note the continuity of Colles and Scarpa fasciae. Inset: Vestibule boundaries and openings onto vestibule. (Reproduced with permission from Corton MM: Anatomy. In Hofman BL, Schorge JO, Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 2016.) outer surface of each labium. On their inner surface, the lateral portion is covered by this same epithelium up to a demarcating line, termed Hart line. Medial to this line, each labium is covered by squamous epithelium that is nonkeratinized. he labia minora lack hair follicles, eccrine glands, and apocrine glands. However, sebaceous glands are numerous (Wilkinson, 2011).


Obstentrics_Williams

Obstentrics_Williams. he clitoris is the principal female erogenous organ. It is located beneath the prepuce, above the frenulum and urethra, and projects downward and inward toward the vaginal opening. The clitoris rarely exceeds 2 cm in length and is composed of a glans, a corpus or body, and two crura (Verkauf, 1992). he glans is usually less than 0.5 cm in diameter, is covered by stratified squamous epithelium, and is richly innervated. he clitoral body contains two corpora cavernosa. Extending from the clitoral body, each corpus cavernosum diverges laterally to form a long, narrow crus. Each crus lies along the inferior surface of its respective ischiopubic ramus and deep to the ischiocavernosus muscle. The clitoral blood supply stems from branches of the internal pudendal artery. Specifically, the deep artery of the clitoris supplies the clitoral body, whereas the dorsal artery of the clitoris supplies the glans and prepuce.


Obstentrics_Williams

Obstentrics_Williams. In adult women, the vestibule is an almond-shaped area that is enclosed by Hart line laterally, the external surface of the hymen medially, the clitoral frenulum anteriorly, and the fourchette posteriorly (see Fig. 2-3). The vestibule is usually perforated by six openings: the urethra, the vagina, two Bartholin gland ducts, and two ducts of the largest paraurethral glands-the Skene glands. he posterior portion of the vestibule between the fourchette and the vaginal opening is called the fossa navic ularis. It is usually observed only in nulliparas.


Obstentrics_Williams

Obstentrics_Williams. Skene glands. he posterior portion of the vestibule between the fourchette and the vaginal opening is called the fossa navic ularis. It is usually observed only in nulliparas. The bilateral Bartholin glands, also termed greater vestibular glands, measure 0.5 to 1 cm in diameter. On their respective side, each lies inferior to the vestibular bulb and deep to the inferior end of the bulbospongiosus muscle (former bulbocavernosus muscle). A duct extends medially from each gland, measures 1.5 to 2 cm long, and opens distal to the hymeneal ring-one at 5 and the other at 7 o'clock on the vestibule. Following trauma or infection, either duct may swell and obstruct to form a cyst or, if infected, an abscess. In contrast, the minor vestibular glands are shallow glands lined by simple mucinsecreting epithelium and open along Hart line.


Obstentrics_Williams

Obstentrics_Williams. he paraurethral glands are a collective arborization of glands whose numerous small ducts open predominantly along the entire inferior aspect of the urethra. he two largest are called Skene glands, and their ducts typically lie distally and near the urethral meatus. Clinically, inlammation and duct obstruction of any of the paraurethral glands can lead to urethral diverticulum formation. The urethral opening or meatus is in the midline of the vestibule, 1 to 1.5 cm below the pubic arch, and a short distance above the vaginal opening. In adult women, the hymen is a membrane of varying thickness that surrounds the vaginal opening more or less completely. Perineal body Fuseddistal segment of urethra & vagina FIGURE 2-4 Vagina and surrounding anatomy. (Reproduced with permission from Corton MM: Anatomy. In Hofman BL, Schorge JO, Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 201o6.)


Obstentrics_Williams

Obstentrics_Williams. Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 201o6.) It is composed mainly of elastic and collagenous connective tissue, and both outer and inner surfaces are covered by nonkeratinized stratified squamous epithelium. he aperture of the intact hymen ranges in diameter from pinpoint to one that admits one or even two ingertips. As a rule, the hymen is torn at several sites during irst coitus. However, identical tears may form by other penetration, for example, by tampons used during menstruation. The edges of the torn tissue soon reepithelialize. In pregnant women, the hymeneal epithelium is thick and rich in glycogen. Changes produced in the hymen by childbirth are usually readily recognizable. For example, over time, the hymen transforms into several nodules of various sizes, termed hymeneal or myrtiform caruncles.


Obstentrics_Williams

Obstentrics_Williams. Proximal to the hymen, the vagina is a musculomembranous tube that extends to the uterus and is interposed lengthwise between the bladder and the rectum (Fig. 2-4). Anteriorly, the vagina is separated from the bladder and urethra by connective tissue-the vesicovaginal septum. Posteriorly, between the lower portion of the vagina and the rectum, similar tissues together form the rectovaginal septum. The upper fourth of the vagina is separated from the rectum by the rectouterine pouch, also called the cul-de-sac or pouch of Douglas. Normally, the anterior and posterior walls of the vaginal lumen lie in contact, with only a slight space intervening at the lateral margins. Vaginal length varies considerably, but commonly, the anterior wall measures 6 to 8 cm, whereas the posterior vaginal wall is 7 to 10 cm. The upper end of the vaginal Posteriorcul-de-sac of Douglas sphincter m. External anal sphincter m.


Obstentrics_Williams

Obstentrics_Williams. Posteriorcul-de-sac of Douglas sphincter m. External anal sphincter m. vault is subdivided by the cervix into anterior, posterior, and two lateral fornices. Clinically, the internal pelvic organs usually can be palpated through the thin walls of these fornices. The vaginal lining is composed of nonkeratinized stratified squamous epithelium and underlying lamina propria. In premenopausal women, this lining is thrown into numerous thin transverse ridges, known as rugae, which line the anterior and posterior vaginal walls along their length. Deep to this, a muscular layer contains smooth muscle, collagen, and elastin. Beneath this muscularis lies an adventitial layer consisting of collagen and elastin (Weber, 1997).


Obstentrics_Williams

Obstentrics_Williams. The vagina lacks glands. Instead, it is lubricated by a transudate that originates from the vaginal subepithelial capillary plexus and crosses the permeable epithelium (Kim, 201l). Due to increased vascularity during pregnancy, vaginal secretions are notably increased. At times, this may be confused with amnionic fluid leakage, and clinical diferentiation of these two is described in Chapter 22 (p. 435). Mter birth-related epithelial trauma and healing, fragments of stratified epithelium occasionally are embedded beneath the vaginal surface. Similar to its native tissue, this buried epithelium continues to shed degenerated cells and keratin. As a result, epidermal inclusion cysts, which are filled with keratin debris, may form. hese are a common vaginal cyst. The vagina has an abundant vascular supply. The proximal portion is supplied by the cervical branch of the uterine artery and by the vaginal artery. he latter may variably arise from the


Obstentrics_Williams

Obstentrics_Williams. The vagina has an abundant vascular supply. The proximal portion is supplied by the cervical branch of the uterine artery and by the vaginal artery. he latter may variably arise from the Vesicovaginal space (filled with loose connective tissue) uterine or inferior vesical artery or directly from the internal iliac artery. The middle rectal artery contributes supply to the posterior vaginal wall, whereas the distal walls receive contributions from the internal pudendal artery. At each level, vessels supplying each side of the vagina course medially across the anterior or posterior vaginal wall and form midline anastomoses. An extensive venous plexus also surrounds the vagina and follows the course of the arteries. Lymphatics from the lower third, along with those of the vulva, drain primarily into the inguinal lymph nodes. Those from the middle third drain into the internal iliac nodes, and those from the upper third drain into the external, internal, and common iliac nodes.


Obstentrics_Williams

Obstentrics_Williams. his diamond-shaped area between the thighs has boundaries that mirror those of the bony pelvic outlet: the pubic symphysis anteriorly, ischiopubic rami and ischial tuberosities anterolaterally, sacrotuberous ligaments posterolaterally, and coccyx posteriorly. An arbitrary line joining the ischial tuberosities divides the perineum into an anterior triangle, also called the urogenital triangle, and a posterior triangle, termed the anal triangle.


Obstentrics_Williams

Obstentrics_Williams. he perineal body is a fibromuscular pyramidal mass found in the midline at the junction between these anterior and posterior triangles (Fig. 2-5). Also called the central tendon of the perineum, the perineal body sonographically measures 8 mm tall and 14 mm wide and thick (Santoro, 2016). It serves as the junction for several structures and provides significant perineal support (Shafik, 2007). Superficially, the bulbospongiosus, superficial transverse perineal, and external anal sphincter muscles converge on the perineal body. More deeply, the perineal membrane, portions of the pubococcygeus muscle, and internal anal sphincter contribute (Larson, 2010). The perineal body Ischiocavernosus m. Cut edge of Colles fascia Bulbospongiosus m. Superficial transverse perineal m. External anal sphincter m. is incised by an episiotomy incision and is torn with second-, third-, and fourth-degree lacerations. Superficial Space of the Anterior Triangle


Obstentrics_Williams

Obstentrics_Williams. External anal sphincter m. is incised by an episiotomy incision and is torn with second-, third-, and fourth-degree lacerations. Superficial Space of the Anterior Triangle This triangle is bounded by the pubic rami superiorly, the ischial tuberosities laterally, and the supericial transverse perineal muscles posteriorly. It is divided into supericial and deep spaces by the perineal membrane. This membranous partition is a dense ibrous sheet that was previously known as the inferior fascia of the urogenital diaphragm. The perineal membrane attaches laterally to the ischiopubic rami, medially to the distal third of the urethra and vagina, posteriorly to the perineal body, and anteriorly to the arcuate ligament of the pubis (see Fig. 2-5) .


Obstentrics_Williams

Obstentrics_Williams. The supericial space of the anterior triangle is bounded deeply by the perineal membrane and supericially by Co lIes fascia. As noted earlier, Colles fascia is the continuation of Scarpa fascia onto the perineum. On the perineum, Co lIes fascia securely attaches laterally to the pubic rami and fascia lata of the thigh, inferiorly to the supericial transverse perineal muscle and inferior border of the perineal membrane, and medially to the urethra, clitoris, and vagina. As such, the superficial space of the anterior triangle is a relatively closed compartment.


Obstentrics_Williams

Obstentrics_Williams. his supericial pouch contains several important structures, which include the Bartholin glands, vestibular bulbs, clitoral body and crura, branches of the pudendal vessels and nerve, and the ischiocavernosus, bulbospongiosus, and supericial transverse perineal muscles. Of these muscles, the ischiocavernosus muscles each attach on their respective side to the medial aspect of the ischial tuberosity inferiorly and the ischiopubic ramus laterally. Anteriorly, each attaches to a clitoral crus and may help maintain clitoral erection by compressing the crus to obstruct venous drainage. he bilateral bulbospongiosus muscles overlie the vestibular bulbs and Crus of clitoriS Cut edge of ischiocavernous m. Levator ani m. �Gluteus maximus m.


Obstentrics_Williams

Obstentrics_Williams. Crus of clitoriS Cut edge of ischiocavernous m. Levator ani m. �Gluteus maximus m. FIGURE 2-5 Superficial space of the anterior perineal triangle and posterior perineal triangle. Structures on the left side of the image can be seen after removal of Colles fascia. Those on the right side are noted after removal of the superficial muscles of the anterior triangle. (Modified with permission from Corton MM: Anatomy. In Hoffman BL, Schorge JO, Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 2016.)


Obstentrics_Williams

Obstentrics_Williams. Bartholin glands. They attach to the body of the clitoris anteriorly and the perineal body posteriorly. The muscles constrict the vaginal lumen and aid release of secretions from the Bartholin glands. They also may contribute to clitoral erection by compressing the deep dorsal vein of the clitoris. The bulbospongiosus and ischiocavernosus muscles also pull the clitoris downward. Last, the superficial transverse perineal muscles are narrow strips that attach to the ischial tuberosities laterally and the perineal body medially. They may be attenuated or even absent, but when present, they contribute to the perineal body (Corton, 2016).


Obstentrics_Williams

Obstentrics_Williams. The vestibular bulbs are almond-shaped aggregations of veins that lie beneath the bulbospongiosus muscle on either side of the vestibule. They measure 3 to 4 cm long, 1 to 2 cm wide, and 0.5 to 1 cm thick. The bulbs terminate inferiorly at approximately the middle of the vaginal opening and extend upward toward the clitoris. Their anterior extensions merge in the midline, below the clitoral body. During childbirth, veins in the vestibular bulbs may be lacerated or even rupture to create a vulvar hematoma enclosed within the supericial space of the anterior triangle (Fig. 41-11, p. 765).


Obstentrics_Williams

Obstentrics_Williams. Deep Space of the Anterior Triangle his space lies deep to the perineal membrane and extends up into the pelvis (Mirilas, 2004). In contrast to the supericial perineal space, the deep space is continuous superiorly with the pelvic cavity (Corton, 2005). It contains portions of urethra and vagina, certain portions of internal pudendal artery branches, and muscles of the striated urogenital sphincter complex (Fig. 2-6).


Obstentrics_Williams

Obstentrics_Williams. Urethra. The female urethra measures 3 to 4 cm and originates within the bladder trigone (p. 28). he distal two thirds of the urethra are fused with the anterior vaginal wall. The epithelialilining of the urethra changes from transitional epithelium proximally to nonkeratinized stratiied squamous epithelium distally. The walls of the urethra consist of two layers of smooth muscle, an inner longitudinal and an outer circular. This is in turn surrounded by a circular layer of skeletal muscle referred to as the sphincter urethrae or rhabdosphincter (see Fig. 2-6). Approximately at the junction of the middle and lower third of the urethra, and just above or deep to the perineal membrane, two strap skeletal muscles called the urethrovaginal sphincter and compressor urethrae are found. Together with the sphincter urethrae, these constitute the striated urogenital sphincter complex. This complex supplies constant tonus and provides emergency relex contraction to sustain continence.


Obstentrics_Williams

Obstentrics_Williams. Distal to the level of the perineal membrane, the walls of the urethra consist of ibrous tissue, serving as the nozzle that directs the urine stream. Here, the urethra has a prominent submucosal layer that is lined by hormonally sensitive stratiied squamous epithelium. Within the submucosal layer on the dorsal (vaginal) surface of the urethra lie the paraurethral glands, described earlier (p. 17). he urethra receives its blood supply from branches of the inferior vesical, vaginal, or internal pudendal arteries. Although still controversial, the pudendal nerve is believed to innervate the most distal part of the striated urogenital sphincter complex. Somatic eferent branches from 52-54 that course along the inferior hypogastric plexus variably innervate the sphincter urethrae.


Obstentrics_Williams

Obstentrics_Williams. Dorsal v. of clitoris Labium minus (cut) Hymeneal ring Sphincter urethrae m.}Striated Compressor urethrae m. urogenital sphincter Urethrovaginal sphincter m. complex Ischiopubic ramus (cut) Perineal membrane Ischiopubic ramus Cut edge of perineal membrane Bulbospongiosus m. (cut) Ischiocavernous m. (cut) Superficial transverse perineal m. External anal sphincter m. Gluteus maximus m. Compressor urethrae m. Urethrovaginal sphincter m. Pubococcygeus }(pubovisceral) m . Pub"ecto'" m. Levator ani mm. . lliococcygeus m."S FIGURE 2-6 Deep space of anterior triangle of the perineum. Structures on the right side of the image can be seen after remova l of the perineal membrane. Also shown are structures that attach to the perineal body: bulbospongiosus, superficial transverse perineal, external anal sphincter, and puboperinealis muscles as well as perineal membrane. (Reproduced with permission from Corton MM: Anatomy. In Hoffman BL, Schorge JO, Bradshaw KD, et al (eds): Gynecology, 3rd ed. New


Obstentrics_Williams

Obstentrics_Williams. sphincter, and puboperinealis muscles as well as perineal membrane. (Reproduced with permission from Corton MM: Anatomy. In Hoffman BL, Schorge JO, Bradshaw KD, et al (eds): Gynecology, 3rd ed. New York, McGraw-Hili Education, 2016.) ·m. External anal sphincter m. Longitudinal smooth m. layer Circular smooth m. layer Plicae transversalis recti


Obstentrics_Williams

Obstentrics_Williams. Internal anal sphincter m . FIGURE 2-7 Anal canal and ischioanal fossa. (Reproduced with permission from Corton MM: Anatomy. In Hoffman BL, Schorge JO, Bradshaw KD, et al (eds): Williams Gynecology, 3rd ed. New York, McGraw-Hili Education, 2016.) Found deep to the anterior and posterior triangles, this broad muscular sling provides substantial support to the pelvic viscera. The pelvic diaphragm is composed of the levator ani and the coccygeus muscles. The levator ani, in turn, contains the pubococcygeus, puborectalis, and iliococcygeus muscles. The pubococcygeus muscle is also termed the pubovisceral muscle and is subdivided based on points of insertion and function. These include the pubovaginalis, puboperinealis, and puboanalis muscles, which insert into the vagina, perineal body, and anus, respectively (Kearney, 2004).


Obstentrics_Williams

Obstentrics_Williams. Vaginal birth conveys signiicant risk for damage to the levator ani or to its innervation (DeLancey, 2003; Weidner, 2006). Evidence supports that levator ani avulsion may predispose women to greater risk of pelvic organ prolapse (Dietz, 2008; Schwertner-Tiepelmann, 2012). For this reason, current research eforts are aimed at minimizing these injuries. his triangle contains the ischioanal fossae, anal canal, and anal sphincter complex, which consists of the internal anal sphincter, external anal sphincter, and puborectalis muscle. Branches of the pudendal nerve and internal pudendal vessels are also found within this triangle.


Obstentrics_Williams

Obstentrics_Williams. Ischioanal Fossae. Also known as ischiorectal fossae, these two fat-filled wedge-shaped spaces are found on either side of the anal canal and comprise the bulk of the posterior triangle (Fig. 2-7). Each fossa has skin as its supericial base, whereas its deep apex is formed by the junction of the levator ani and obturator internus muscles. Other borders include: laterally, the obturator internus muscle fascia and ischial tuberosity; inferomedially, the anal canal and sphincter complex; superomedially, the inferior fascia of the downwardly sloping levator ani; posteriorly, the gluteus maxim us muscle and sacrotuberous ligament; and anteriorly, the inferior border of the anterior tri angle.


Obstentrics_Williams

Obstentrics_Williams. The fat found within each fossa provides support to surrounding organs yet allows rectal distention during defecation and vaginal stretching during delivery. Clinically, injury to vessels in the posterior triangle can lead to hematoma formation in the ischioanal fossa, and the potential for large accumulation in these easily distensible spaces. Moreover, the two fossae communicate dorsally, behind the anal canal. This can be especially important because an episiotomy infection or hematoma may extend from one fossa into the other. Anal Canal. his distal continuation of the rectum begins at the level of levator ani attachment to the rectum and ends at the anal skin. Along this 4-to 5-cm length, the mucosa consists of columnar epithelium in the uppermost portion. However, at the pectinate line, also termed dentate line, simple stratified squamous epithelium begins and continues to the anal verge. At the verge, keratin and skin adnexa join the squamous epithelium.


Obstentrics_Williams

Obstentrics_Williams. The anal canal has several tissue layers (see Fig. 2-7). Inner layers include the anal mucosa, the internal anal sphincter, and an intersphincteric space that contains continuation of the rectum's longitudinal smooth muscle layer. An outer layer contains the puborectalis muscle as its cephalad component and the external anal sphincter caudally. Within the anal canal, three highly vascularized submucosal arteriovenous plexuses, termed anal cushions, aid complete closure of the canal and fecal continence when apposed. Increasing uterine size, excessive straining, and hard stool create increased pressure that ultimately leads to degeneration and subsequent laxity of the cushion's supportive connective tissue base. These cushions then protrude into and downward through the anal canal. This leads to venous engorgement within the cushionsnow termed hemorrhoids. Venous stasis results in inflammation, erosion of the cushion's epithelium, and then bleeding. internus m. Pudendal n.


Obstentrics_Williams

Obstentrics_Williams. internus m. Pudendal n. External hemorrhoids are those that arise distal to the pectinate line. They are covered by stratiied squamous epithelium and receive sensory innevation from the inferior rectal nerve. Accordingly, pain and a palpable mass are typical complaints. Following resolution, a hemorrhoidal tag may remain and is composed of redundant anal skin and ibrotic tissue. In contrast, internal hemorrhoids are those that form above the pectinate line and are covered by insensitive anorectal mucosa. hese may prolapse or bleed but rarely become painful unless they undergo thrombosis or necrosis.


Obstentrics_Williams

Obstentrics_Williams. Anal Sphincter Complex. Two sphincters surround the anal canal to provide fecal continence-the external and internal anal sphincters. Both lie near the vagina and may be torn during vaginal delivery. he internal anal sphincter (lAS) is a distal continuation of the rectal circular smooth muscle layer. It receives predominantly parasympathetic ibers, which pass through the pelvic splanchnic nerves. long its length, this sphincter is supplied by the superior, middle, and inferior rectal arteries. he lAS contributes the bulk of anal canal resting pressure for fecal continence and relaxes prior to defecation. The lAS measures 3 to 4 cm in length, and at its distal margin, it overlaps the external sphincter for 1 to 2 cm (DeLancey, 1997). he distal site at which this overlap ends, called the intersphincteric groove, is palpable on digital examination.


Obstentrics_Williams

Obstentrics_Williams. In contrast, the external anal sphincter (EAS) is a striated muscle ring that anteriorly attaches to the perineal body and posteriorly connects to the coccyx via the anococygealiligament. The EAS maintains a constant resting contraction to aid continence, provides additional squeeze pressure when continence is threatened, yet relaxes for defecation. he external sphincter receives Posterior labial n. Ischiocavernosus m. Bulbospongiosus m. perineal m. Perineal n. Pudendal n. sphincter m. Levator ani mm. blood supply from the inferior rectal artery, which is a branch of the internal pudendal artery. Somatic motor ibers from the inferior rectal branch of the pudendal nerve supply innervation. Clinically, the AS and EAS may be involved in third-and fourthdegree lacerations during vaginal delivery, and reunion of these rings is integral to defect repair (Chap. 27, p. 532).


Obstentrics_Williams

Obstentrics_Williams. This is formed from the anterior rami of S24 spinl nerves. It courses between the piriformis and cocygeus muscles and exits through the greater sciatic foramen at a location posterior to the sacrospinous ligament and just medil to the ischial spine (Barber, 2002; Maldonado, 2015). Thus, when injecting local anesthetic for a pudendal nerve block, the ischial spine serves an identifiable landmark (Chap. 25, p. 489). The pudendal nerve then runs beneath the sacrospinous ligament and above the sacrotuberous ligament as it reenters the lesser sciatic foramen to course along the obturator intern us muscle. Atop this muscle, the nerve lies within the pudendal canal, also known as Alcock canal, which is formed by splitting of the obturator internus investing fascia (Shafik, 1999). In general, the pudendal nerve is relatively fixed as it courses behind the sacrospinous ligament and within the pudendal canal. Accordingly, it may be at risk of stretch injury during downward displacement of the


Obstentrics_Williams

Obstentrics_Williams. pudendal nerve is relatively fixed as it courses behind the sacrospinous ligament and within the pudendal canal. Accordingly, it may be at risk of stretch injury during downward displacement of the pelvic floor during childbirth (Lien, 2005).


Obstentrics_Williams

Obstentrics_Williams. he pudendal nerve leaves this canal to enter the perineum and divides into three terminal branches (Fig. 2-8). The first of these, the dorsal nerve of the clitoris, runs between the ischiocavernosus muscle and perineal membrane to supply the clitoral glans (Ginger, 2011 b). Second, the perineal nerve runs supericial to the perineal membrane (Montoya, 201l). It divides into Ilioinguinal & genitofemoral nn. branches Glans & crus of clitoriS sphincter mm. /' Perineal membrane with window that exposes striated urogenital sphincter mm. Dorsal n. & a. of Perineal n. & a. Perineal branch of cutaneous n. Inferior rectal n. & a. Gluteus maximus m.