Natural family planning part 1- Medical overview

NFP is not a single method. Rather, it is a group of different “methods for planning and preventing pregnancies by observation of the naturally occurring signs and symptoms of the fertile and infertile phases of the menstrual cycle, with the avoidance of intercourse during the fertile phase if pregnancy is to be avoided.” (World Health Organization, 1982)

When barrier methods (condoms, diaphragms, etc.) are used at the fertile time instead of abstinence from genital contact, then these methods are called â€œfertility awareness combined methodsâ€? (FACM).

Effective for avoiding pregnancy
Can be used to conceive
No side effects
High user satisfaction and continuation rates (70-90%)
Increased couple communication and intimacy
Comparatively inexpensive
Insight into normal and abnormal functioning of the womanâ€™s reproductive system

Abstinence is required for 9 or more consecutive days mid-cycle (depending on the method and the womenâ€™s cycles). Studies suggest that couples using NFP have intercourse about as often as most couples using other methods (5-6 times per month), but more concentrated into the infertile days.
FAC methods do not require abstinence, just use of barriers on fertile days, but have somewhat higher pregnancy rates than pure NFP methods.
NFP provides no protection against sexually transmitted infection.

Physiologic basis
NFP is based on the fact that there are about 6 days of a womenâ€™s menstrual cycle (perhaps more properly called the reproductive cycle) when insemination can result in pregnancy (the 5 days before ovulation and the day of ovulation itself). There is some imprecision in identifying these 6 days, which is why 9 (or sometimes more) days of fertility are usually identified by an NFP method. The most effective symptom for identifying the approach of ovulation is the change in a womenâ€™s vaginal discharge that results from a change in the fluid produced by the cervix, or opening of the womb. The cervical fluid (cervical mucus) changes in its chemical and physical properties in order to allow for sperm survival for up to 5 days until ovulation occurs. The woman observes a discharge that is progressively more stretchy, slippery, and clear. Then it abruptly reduces after ovulation. Basal body temperature also rises after ovulation. Calendar calculations have also been used to define the fertile days of the menstrual cycle and are still sometimes used, but they are less accurate. Reproductive hormones can also be measured in urine, but this is generally no more accurate than the careful observation of vaginal discharge. Some women say that they find it helpful to identify their fertile days by feeling their own cervix with their fingers, but this is not generally necessary and the systematic medical evidence for feeling the cervix is weak. Saliva monitors have shown to be NOT reliable. Ovulation pain (mittelschmerz) does occur in many women, but it can occur before, during, or after ovulation.

Measuring effectiveness
Pregnancy rates are reported as percentages during one year of perfect use or typical use. Perfect use means use exactly as directed. Typical use means what couples actually do, including errors and changes of intention. I will talk here just about effectiveness to avoid pregnancy. Effectiveness to conceive is another topic. Most pregnancies that occur during NFP use result from sexual intercourse at a time that a couple knows to be fertile, according to the NFP method. There are few true surprise pregnancies with NFP. Typical use pregnancy rates vary very widely between studies, because the characteristics and motivations of the population vary widely. Quality and amount of instruction in NFP also impacts pregnancy rates for NFP users. To maximize effectiveness usually requires personal instruction from an experienced teacher.

4 comments for “Natural family planning part 1- Medical overview

  1. Anonymous for this
    January 8, 2006 at 11:55 pm

    . . . Studies suggest that couples using NFP have intercourse about as often as most couples using other methods (5-6 times per month) . . .

    In my own marriage “5-6 times per month” would be a very radical change from our current schedule, and not a good one. Does NFP work at all for people who want to have sex more than “5-6 times per month”? (I shudder to even type that. Are most people really so unconcerned with sex?)

  2. Matthew Crowley
    January 9, 2006 at 1:25 am

    While I don’t doubt that the method decribed about can be effective birth control, I see two problems:

    1. Far to easy to mess up (which leads to #2)

    2. If there is any question in either partner’s mind about whether it WILL be effective and the desire in not to be pregnant…hard to think of a bigger turn off. I think that most of the men will agree with me that the list of potential turnoffs need not be lengthened. Much easier to use something that requires less thought process (I realize part of the point is to increase the thought process but my point is relative to the bed room where I doubt much family is occurring in any case).

  3. anon me too
    January 10, 2006 at 10:27 pm

    When we used NFP, my cycles were 27 days and we identified usually 9 as fertile. So anon, that meant there were about 5 days in a row at the begining of the cycle, then 9 days off, then 13 days usable at the end. and if those middle days are hard, you can bring out a condom (then the effectiveness reverts to the condom’s rate, not the 98% for perfect-use NFP)

    We did this for 3 years and when we wanted to conceive, it worked on the 1st try, 5 times. so we’re highly fertile. (On conception… not so good at carrying to term, unfortunately). but NFP did work for very fertile, very regular-cycled me.

  4. Kari
    February 8, 2006 at 11:20 pm

    I am currently using NFP as a newlywed. So, we just use other protection during the fertile days. It is a lot to learn, but it’s WELL worth it, because you are so aware of what’s going on with your body. It also was a better route for us, since we didn’t want to use hormonal birth control…for various reasons. Yes, the condoms are considered less effective, but if used correctly, their rates are pretty high up there too, and it’s not for the whole month. So, as far as it being an inconvienience, well it’s not really. Anyway, we like it.

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