The use of alpha fetoprotein in prenatal diagnosis.

Maternal or blood levels of alpha fetal protein are elevated in the presence of certain fetal anomalies, particularly those of the neural tube in which protein from the cerebrospinal fluid may leak into the amniotic fluid. Since this is a nonspecific elevation, other diseases are potentially screened for by this determination. Alpha fetal protein levels should be measured on any amniotic fluid samples obtained during the middle trimester of pregnancy.