Maternal serum alpha-fetoprotein in twin pregnancy.
Maternal serum alpha-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 alpha-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 alpha-fetoprotein values correlated significantly with increasing incidence of fetal and neonatal death, premature delivery (less than 35 weeks' gestation), and twin-to-twin birth discordance (greater than 20%), most pronounced at greater than 4 multiples of the singleton median level. A significant negative correlation between alpha-fetoprotein and birth weight was observed (p less than 0.001), but was related more to prematurity than to poor fetal growth. Theoretically, serum alpha-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 alpha-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.
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Manitoba, Winnipeg, Canada.
J M
JM
Johnson
C R
CR
Harman
J A
JA
Evans
K
K
MacDonald
F A
FA
Manning
D005260:Female; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000097:blood*; D012016:Reference Values; D014427:Twins; D000509:alpha-Fetoproteins / Q000032:analysis*
D000509:alpha-Fetoproteins