Prenatal diagnosis during pregnancy is recommended for pregnant women aged 45 years, with amniocentesis being the most common test, and non-invasive DNA testing being used if firmly refused. For pregnant women aged 35 years or older, prenatal diagnosis is recommended during pregnancy, which can detect chromosome number and structure abnormalities, sex-linked genetic diseases, and inherited metabolic defects, while non-invasive DNA can only detect the three most common chromosome abnormalities of trisomy 13, 18, and 21, and non-invasive DNA is recommended if there is a contraindication to or a firm refusal of amniocentesis. In addition to pregnant women of advanced age, amniocentesis is also recommended in cases where amniotic fluid is abnormal, Down’s syndrome screening suggests a high risk, non-invasive DNA suggests a critical risk or higher, and there are fetal developmental abnormalities or structural malformations.