Most pregnant women in their 40s are recommended to opt for amniocentesis. Pregnant women in their 40s are of advanced maternal age and are at high risk for birth defects, requiring prenatal diagnosis to determine whether the fetus has inherited a metabolic disease. Prenatal diagnosis is needed to determine whether the fetus has any inherited metabolic diseases. 40-year-old pregnant women have a higher chance of fetal malformations, and amniocentesis is recommended for a definitive diagnosis. Amniocentesis carries risks of miscarriage and fetal loss. 40-year-old pregnant women with signs of miscarriage or infection that preclude amniocentesis can undergo noninvasive prenatal screening. The main advantage of non-invasive prenatal screening is that it is non-invasive and has a lower false positive rate. It is important to note that non-invasive prenatal screening is a screening test, not a prenatal diagnosis, and does not lead to a final diagnosis. If there is an abnormality on prenatal screening, amniocentesis is still needed to give a definitive diagnosis. 40-year-old pregnant women should consult the prenatal diagnosis clinic in a timely manner, complete various tests under the guidance of a professional doctor, and give appropriate treatment.