 Among cases that are detected by routine amniocentesis or chorionic villus sampling, one study found that the prevalence of Turner syndrome among tested pregnancies was 5.58 and 13.3 times higher, respectively, than among live neonates in a similar population.The rate of cardiovascular malformations among patients with Turner syndrome ranges from 17% to 45%.The variations found in the different studies are mainly attributable to variations in noninvasive methods used for screening and the types of lesions that they can characterize.