MATERNAL SERUM ALPHA-FETOPROTEIN IN TWIN PREGNANCY

Maternal serum α-fetoprotein concentration was measured at 14 to 20 weeks' gestation in 138 twin pregnancies. All patients had at least one ultrasonographic examination (86% before 20 weeks' gestation). Two pregnancies were discordant for open fetal defects (one anencephaly, one gastroschisis). The median serum α-fetoprotein value in the remaining 136 twin pregnancies paralleled a curve 2.5 times the median curve for singleton pregnancies over the gestational range studied. Higher serum α-fetoprotein values correlated significantly with increasing incidence of fetal and neonatal death, premature delivery (<35 weeks' gestation), and twin-to-twin birth discordance (>20%), most pronounced at >4 multiples of the singleton median level. A significant negative correlation between α-fetoprotein and birth weight was observed (p < 0.001), but was related more to prematurity than to poor fetal growth. Theoretically, serum α-fetoprotein screening detected 56.5% of the twins in this study when a cutoff level of 2.5 multiples of the median was used, enhancing twin detection in the study population by 40%. These data indicate that maternal serum α-fetoprotein screening has a valuable role in the management of twin pregnancy, both in the detection of twins and in the prediction of perinatal outcome in twin pregnancy. © 1990.