If a fetus has a chromosomal abnormality, it can be manifested as a variety of organ malformation or mental retardation, which cannot be treated after birth, and is a disease that seriously affects the quality of the population born. The following cases require amniocentesis to check fetal chromosomes: 1. If the pregnant woman is over 35 years old, she is of advanced age and is prone to fetal chromosomal abnormalities during pregnancy and childbirth; 2. She has delivered a child with chromosomal abnormalities in the past; 3. She has a history of multiple fetal stoppages or stillbirths; 4. Check the baby’s chromosomes.