Alpha‐fetoprotein Levels in Amniotic Fluid in Normal Pregnancy and in Pregnancy Complicated by Anencephaly

Summary Amniotic fluid levels of alpha–fetoprotein were measured in 93 patients with normal uncomplicated pregnancies and in 10 patients with anencephalic fetuses. The amniotic fluid levels in normal pregnancies between 12 and 41 weeks' gestation are presented. In all the pregnancies with anencephaly the alpha‐fetoprotein levels were significantly raised above the normal range. Two patients who had previously had an anencephalic fetus are also reported.