[Prenatal alpha fetoprotein screening for defects in the neural tube]

Abstract

Abnormally increased alpha1-fetoprotein (AFP) in the serum of women in the 16th--18th week of pregnancy defines a group of individuals with a high risk for open neural tube defects (spina bifida and anencephaly). Repeated measurement of AFP, ultrasound and further clinical examination serve to exclude other situations associated with high serum AFP such as threatened or missed abortion, wrongly estimated duration of pregnancy, twins, etc. Suspicion of fetal neural tube defect can be substantiated by measurement of AFP in the amniotic fluid following amniocentesis to an extent which renders interruption of pregnancy justifiable. A symposium held in Zurich is reported whose purpose was to summarize the present state of knowledge and discuss the possibility of a screening program for Switzerland. It is estimated that in this country 0.8--1.3 cases of spina bifida and 0.1--1 case of anencephaly per 1000 births occur, rendering screening justifiable. The points which prompted most discussion were ethical questions. A Swiss study group was constituted for further evaluation of the matter.