title: Neural tube defects: maternal serum screening and prenatal diagnosis.
abstract: Neural tube defects represent some of the most common and serious of the congenital malformations. Although elevation of alpha-fetoprotein in amniotic fluid is not diagnostic, it does indicate an abnormality of the fetus in a very high proportion of cases. A normal level, however, does not exclude the possibility of a closed neural tube defect. It is therefore recommended that all amniocenteses performed between 15 and 20 weeks of gestation include measurement of alpha-fetoprotein. Maternal serum alpha-fetoprotein assay is a screening test and pilot studies will be necessary to determine its value as a routine prenatal blood test.
mesh_terms: D000649:Amniocentesis; D000653:Amniotic Fluid / Q000032:analysis; D005260:Female; D005817:Genetic Counseling; D006801:Humans; D009436:Neural Tube Defects / Q000175:diagnosis*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012306:Risk; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D000509:alpha-Fetoproteins