Prenatal diagnosis policy without routine amniocentesis in pregnancies with a positive family history for neural tube defects.

The recurrence risk for neural tube defects in pregnancies of women with a family history of neural tube defects greatly exceeds the general population risk. In these high risk pregnancies, we used a prenatal diagnostic method differing from that usually employed, relying mainly on the results of maternal serum alpha-fetoprotein (MSAFP) and ultrasound examination, without routine amniocentesis. During the 6 years reviewed in this study, this method was applied in 539 pregnancies. Of a total of 20 neural tube defects, 19 were detected using this combination of MSAFP, ultrasound, and selective amniocentesis, and the authors estimate that about 8-10 spontaneous abortions were avoided because only 28 amniocenteses were carried out instead of 539. The risk of recurrence was found to be lower than that experienced earlier.