Amniocentesis is mainly used for the diagnosis of fetal congenital developmental abnormalities, fetal hereditary diseases and fetal metabolic diseases, mainly including: 1. During the embryonic period, due to the influence of harmful factors such as drugs or viral infections, which may cause the baby to develop abnormalities, if the possibility of the baby developing abnormalities is considered during the general examination, amniocentesis can be performed to further confirm the diagnosis, such as Cleft lip and palate; 2. Amniocentesis is also used for prenatal diagnosis of chromosomal abnormalities such as Down’s syndrome and trisomy 18; 3. For pregnant women who need paternity testing for special reasons, the results of paternity testing through amniotic fluid are more accurate.