What is amniocentesis? Amniocentesis is a prenatal examination method that punctures the abdominal wall and uterine wall of pregnant women to remove fetal cells and amniotic fluid from the amniotic fluid for testing to find out whether the fetus has chromosomal aberrations, genetic diseases and other abnormalities. Pregnant women need to undergo amniocentesis between 16 and 24 weeks of pregnancy based on doctor\’s advice. amniocentesis