According to animal experiments and clinical observations, the effects of drugs on embryos and fetuses can be roughly divided into three types: positive teratogenicity, possible teratogenicity and potential harm. Of course, their boundaries are not very strict. Be aware of the following classes of drugs that are more obviously harmful. Anti-cancer drugs: can cause malformations, stillbirth, missing limbs, external ear deformities, cleft lip and palate, hydrocephalus, etc. Hormone drugs: It is reported that girls born to pregnant women who use estrogen early may develop sex hormones during puberty.