The final results of amniocentesis are based on karyotyping and diagnosis of chromosomal genetic disorders. Amniocentesis is recommended for pregnant women over 34 years of age, those with Down’s syndrome in their family, those with NT test suggesting fetal nuchal translucency anomalies, and those with high risk of Down’s screening results, for fetal karyotyping and diagnosis of chromosomal genetic diseases. Amniocentesis is usually done in the 16th to 24th week of pregnancy. In the middle of pregnancy, the fetus is small, the amount of amniotic fluid is large, and the fetus floats in the amniotic fluid, so it is not advisable to injure the fetus when extracting the amniotic fluid, and the amniotic fluid and amniotic fluid cells can be used to make a diagnosis of chromosomal or genetic disorders through chromosomal karyotyping and molecular biology methods. In addition, regular checkups are required during pregnancy to detect abnormalities in a timely manner.