Amniocentesis is a prenatal diagnostic test typically performed between the 15th and 20th weeks of pregnancy. This procedure involves carefully extracting a small sample of amniotic fluid from the amniotic sac surrounding the fetus. The amniotic fluid, which protects and supports the developing baby, contains fetal cells. The collected sample is then analyzed in a laboratory to evaluate the baby's genetic and chromosomal health, helping to identify potential genetic disorders.