1. Commonly used drugs with potential harm to the embryo or fetus Reaction stop: sedative-hypnotic drugs Taken within 27-42 days after conception: short limb malformation (absence of long bones in the upper or lower limbs). Taken outside the short limb deformity period: congenital malformations of other organs (malformation of the outer ear or heart). Vitamin A: nutritional guidelines call for a daily intake of VitA 10 000 IU intake > 15 000 IU for pregnant women with an increased risk of congenital malformations. Isotretinoin, aromatic retinoic acid. Hormones: androgens (testosterone): masculinization of external genitalia in female infants. Danazol: testosterone derivative, weak androgenic effect. Ethylene estradiol: uterine dysplasia, vaginal cervical clear cell adenocarcinoma, testicular hypoplasia, cryptorchidism. Anticonvulsants: Hain, phenytoin: Hain syndrome (craniofacial dysmorphism, cleft palate, nasal septum exostosis, growth defects, mental development defects), carbamazepine is relatively safe for use during pregnancy. Epilepsy itself is a risk factor for inducing malformations, so it is sometimes difficult to determine whether it is epilepsy or the anticonvulsant drugs used to treat it, or a combination of both, that causes fetal malformations. Anticoagulants: warfarin, bicoumarin: small molecular weight, can pass through the placenta. In early pregnancy, warfarin causes warfarin embryopathy (nasal hypoplasia, spinal malformations) and in late pregnancy, causes fetal cranial hemorrhage, microcephaly, blindness, mental retardation. Antibiotics: tetracycline: second and third generation cephalosporins containing N-methylthiotetrazolium chain: testicular dysplasia. Chinese medicine: smallpox powder, honeysuckle, echinacea, peony bark, rhubarb, mangosteen, aloe vera, senna, barley, safflower, peach kernel, motherwort, semen, sour date, musk. 2. Management of pregnant women exposed to drugs during pregnancy To date, this remains a challenge: 1. The etiology of most malformations is unknown (60-70%). 20-25% are attributed to genetic abnormalities and <1% are drug-related, but many patients, lawyers often suspect that fetal exposure to drugs causes malformations. 2. Risk is difficult to assess: few teratogens are known, and most drugs have incomplete information to assess their teratogenic risk and side effects on the fetus.