Generally speaking, physicians use drugs for pregnant women based on the classification of the drug to determine how much it affects the fetus. Clinically, drugs are classified into five classes according to the degree of harm, including A, B, C, D and X. “Class A” means no effect on the human fetus; “Class B” means possible effect on animals but no effect on humans; “Class C” means effect on animals but human Class “D” has effects on humans, but can be used if the benefits of the drug are greater than the harm to the fetus. For example, many drugs used to treat epilepsy must be used when a pregnant woman has epilepsy, as do antithyroid drugs; “Class X” is a drug that is determined to have an effect in humans and that outweighs any possible benefit, so it cannot be used. Drugs that cannot be used at all during pregnancy, such as some anti-cancer drugs, some psychiatric drugs, sleeping pills, etc. First of all, antibiotics are the most common, including chloramphenicol, tetracycline, streptomycin, kanamycin, gentamicin, neomycin, ashwagandha, mycobacterium, clotrimazole, polymyxin E, polymyxin B, vancomycin, sulfonamides, rifampin, and remifentan, etc. Take tetracycline as an example, regular dose can cause fetal teeth, bone pathway dysplasia, enamel defects, gray teeth, brown teeth or yellow teeth and short limb deformities, congenital cataracts, etc. Large doses can also induce fatal hepatic steatosis. Antipyretic and analgesic drugs such as aspirin and finasteride are likely to cause fetal malformations of the bone path, neurological or renal malformations after use by pregnant women, and some lead to hemolysis of the newborn causing head hematomas and other bleeding tendencies. Sedative sleeping drugs such as Valium can cause congenital malformations in the fetus; Mildron causes fetal growth retardation and congenital heart disease; barbiturates cause finger and toe shortening and nostril passages. Hormones such as estrogen cause shortage of upper limbs, vaginal adenopathy in female infants and feminization in male infants. Progestins can cause masculinization in female infants and hypospadias in male infants. Cortisone can cause anencephaly, cleft lip and palate, and low weight deformities. Thyroxine can also cause malformations. Glucose-lowering drugs such as eugenol, damacell, and toluenesulfonylurea can cause fetal malformation or death. Antimalarials such as quinine, chloroquine, and adipine can cause congenital deafness, nerve damage, and thrombocytopenia in the fetus. The anti-cancer drug cyclophosphamide causes limb defects and cleft palate; the antipsychotic drug chlorpromazine causes retinopathy; the antiepileptic drug phenytoin sodium causes finger deformity and crotch cleft; the antiallergic drugs paracetamol and benadryl can cause limb defects; the contraceptive drug can cause congenital heart disease and limb shortage in the fetus. Many people regard vitamins as safe and nutritious medicines, but vitamins can cause fetal malformation is often overlooked. Vitamin A can destroy fetal cartilage cells, leading to bone path deformities, finger and toe deformities, cleft palate, eye deformities and brain deformities; vitamin D increases fetal blood calcium, which can cause fetal mental retardation. It has been reported that taking large amounts of vitamin C and B during pregnancy can also cause fetal malformations. Inappropriate use of Chinese herbs also has adverse effects on the development of the fetus. Such as safflower, heliotrope, pu huang, musk, angelica, ginseng, etc., especially ginseng as a “tonic”, a variety of compound preparations, such as ginseng royal jelly, ginseng essence, ginseng cream, ginseng tincture, ginseng wine, ginseng nourishing glory pill, ginseng large tonic nine, ginseng essence, youth treasure, etc.; and ginseng wolfberry soup, ginseng silver ear soup, etc., pregnant women There is nothing wrong with strengthening nutrition, but it is not known that these herbs have the effect of stimulating the uterus, which can lead to intrauterine ischemia and hypoxia of the fetus, resulting in fetal stunting or malformation. The rhubarb, mannitol, rhubarb, shanglu, croton, petunia, gansui, etc., by stimulating the intestinal tract, reflexively cause strong contractions of the uterus, resulting in fetal miscarriage and premature birth. Some herbs are toxic in themselves, such as zebrawood, raw nancellus, sophora, aconite, artemisia, Sichuan pepper, centipede, vermilion, and strophanthus, etc., which can directly or indirectly affect fetal development. There are also some Chinese medicines such as Qilisan, Xiaohuoluo Wan, Niuhuang Detoxification Pills (Tablets), Niuhuang Shangqing Wan (Tablets), Zai Zai Wan, Suhe Xiang Wan, Live Blood Pain Relief Pills, Guanxin Suhe Jiu, Gentian Diarrhea Liver Jiu, and Pianzi Rizhong Wan should also be prohibited or used with caution. In summary, there are indeed many drugs that have an effect on the fetus (the above list is only the commonly used part), which sounds terrible and is true. The intention is to draw the attention of pregnant women to avoid the use of drugs that are prohibited or cautiously used by pregnant women, but many herbal or proprietary Chinese medicines are in the form of compounding, which requires a high degree of vigilance. The first principle to grasp is not to take medication for the slightest problem, of course, it does not mean that you do not take medication, the right attitude is to seek medical attention in a timely manner, explain to the doctor that you are pregnant, the doctor will weigh the pros and cons, choose safe drugs without toxic side effects, to ensure the safety and health of the fetus.