A child with trisomy 21 can still have a normal pregnancy, but it is important to note that the fetus in the next pregnancy may still have trisomy 21. It is recommended that both spouses undergo tests to determine if there are any chromosomal abnormalities before pregnancy. If there is no abnormality, it is less likely that a fetus with trisomy 21 will be conceived again; if there is an abnormality, it is more likely. If the chromosomal test reveals that there is no abnormality in both spouses, it is also important to avoid adverse factors such as smoking, alcohol consumption, and medication during pregnancy before the next pregnancy. Avoiding adverse factors reduces the incidence of fetuses with trisomy 21. If the conception is successful, it is recommended to improve the prenatal diagnosis, such as amniocentesis at 16 to 22 weeks of pregnancy, which can clarify whether the fetus has 21-trisomy syndrome. In addition, prolonged exposure to toxic substances such as pesticides and radiation in the early and middle stages of pregnancy can also increase the risk of fetal disease.