Outcome of pregnancy in relation to maternal serum alpha-fetoprotein levels in the second trimester. An evaluation of a screening program and a longitudinal follow-up.

120 women with elevated alpha-fetoprotein (AFP) in pregnancy week 16-17 were subsequently supervised every 4th week until a few days postpartum. A group of 102 women with normal (n = 78) or low (n = 24) serum AFP concentrations in pregnancy week 16-17 were studied in the same way. In the last week before parturition the AFP serum level declined and the decrease was more pronounced with increasing gestational duration up to pregnancy week 41. The AFP level relationship between the women was stable on average throughout the pregnancies. Smoking was found to be related to elevated maternal serum AFP levels in pregnancy week 16-17. Among mothers younger than 25 years, 72% of those with high or very high AFP serum levels in pregnancy week 16-17 were smokers. Among women with elevated or much elevated maternal serum AFP levels in pregnancy week 16-17, male fetuses predominated. But only those carrying female fetuses gave premature birth to small-for-date children. Further analysis of the data revealed that if such a woman was a multipara, there was a 54% risk of a small-for-date premature female baby. Other data indicate that this risk may be increased by smoking and maternal age. It is recommended that this category of mothers with elevated AFP in pregnancy week 16-17 is continuously supervised during pregnancy.