Amniocentesis
Examination of a sample of amniotic fluid makes possible the prenatal diagnosis of chromosomal anomalies and certain metabolic defects. The procedure can be used as early as 14th week of pregnancy when abortion of the affected fetus is still feasible. The diagnosis of chromosomal anomalies is made by culture and kryotyping of fetal cells from the amniotic fluid, and of metabolic defects by biochemical analysis of fluid.