Second-trimester maternal serum alpha-fetoprotein and risk of adverse pregnancy outcome

Objective: To determine the risk of adverse pregnancy outcome by maternal s erum alpha-fetoprotein (MSAFP) level. Methods: We followed 77,149 pregnant women and their infants from MSAFP scr eening in the 15th to 20th week of gestation until 1 year after birth. info rmation on pregnancy outcome was obtained from national registries. The rel ative risks (RRs) and 95% confidence intervals (CIs) for adverse pregnancy outcome were estimated according to the level of MSAFP, with adjustment for confounders. Results: A total of 638 pregnancies resulted in spontaneous abortion, 289 i n stillbirth, and 437 in infant death. Compared with women with MSAFP level s at 0.75-1.24 multiples of the median (MoM), those with MSAFP levels great er than or equal to 2.5 MoM had an increased risk of spontaneous abortion ( RR 12.5; 95% CI 9.7, 16.1), preterm birth (RR 4.8; 95% CI 4.1, 5.5), small for gestational age (RR 2.8; 95% CI 2.4, 3.2), low birth weight (RR 5.8; 95 % CI 5.0, 6.6), and infant death (RR 1.9; 95% CI 1.2, 2.8). Women with MSAF P levels below 0.25 MoM had an increased risk of spontaneous abortion (RR 1 5.1; 95% CI 9.3, 24.8), preterm birth (RR 2.2; 95% CI 1.3, 3.8), and stillb irth (RR 4.0; 95% CI 1.0, 16.0); those with levels less than 0.5 MoM had an increased risk of infant death (RR 1.9; 95% CI 1.2, 3.0). The increased ri sk of infant death remained after the subtraction of recognized conditions associated with extreme MSAFP values. Conclusion: Pregnant women with extreme MSAFP values in the second trimeste r have an increased risk of fetal and infant deaths. Obstet Gynecol 2001;97 :277-82. (C) 2001 by The American College of Obstetricians and Gynecologist s.).