Alpha-fetoprotein and the prenatal diagnosis of central nervous system disorders. A review.

The use of amniotic fluid alpha-fetoprotein measurements in the early prenatal diagnosis of central nervous system disorders is reviewed. The method is sensitive and specific and has had a pronounced effect on the counselling of mothers who have already had a child with spina bifida or anencephaly. Measurement of other amniotic fluid components, such as fetal macrophages, beta-trace protein, alpha2-macroglobulin or fibrinogen-degradation products, is less reliable and these should not be used in making primary diagnoses. The assay of alpha-fetoprotein in maternal serum shows signs of being a useful preliminary screening process, and may identify pregnancies where amniocentesis and confirmatory amniotic fluid determinations should be offered.