Amniocentesis is a prenatal diagnostic procedure that involves sampling amniotic fluid from the amniotic sac using a fine needle inserted through the maternal abdomen. The fluid contains fetal cells and biochemical substances, which are analyzed to detect chromosomal abnormalities, genetic disorders, and fetal infections. It is typically performed between 15 and 20 weeks of gestation. This procedure is distinct from fetal blood sampling or other monitoring techniques. The core clinical concept is that amniotic fluid analysis provides direct information about the fetus’s genetic and metabolic status without causing significant harm when performed correctly by experienced clinicians.

Reference: Williams Obstetrics, Cunningham et al., 25th Edition.