In the clinic, we often come across patients who have skin diseases or other diseases after pregnancy, one of them has a lot of concerns about medication during pregnancy and even refuses to take all medications, thus delaying the disease; another group of pregnant women choose medications blindly, resulting in unreasonable medication causing fetal malformation or miscarriage, which brings great harm to their body and mind. At present, the reference of pregnancy medication is mainly based on the U.S. FDA’s pregnancy safety drug classification, the FDA pregnancy safety medication is divided into the following five categories. 1. Drugs that have been shown to be safe in both animal experiments and human test results. 2. Drugs that have been shown to be safe in animal studies, or drugs that have been shown to be unsafe in animal studies and safe in human studies. 3, animal testing showed unsafe and human testing was not done. 4.Drugs that human trials have shown to be harmful to the fetus but can be considered when the pregnant woman has a serious illness. X. Prohibited. Pregnant patients should try to choose Class A and Class B drugs. There are relatively few drugs belonging to Class A, including levothyroxine, folic acid, and multivitamins during pregnancy; Class B drugs include penicillins as well as cephalosporin antibiotics; >60% of drugs are classified into Class C, which belong to the category of drugs that cannot be ruled out as harmful, but at the same time the potential benefits exceed the potential harms; for serious diseases, whether to use Class D drugs during pregnancy needs to be weighed against the pros and cons; Class X drugs should be absolutely forbidden during pregnancy, for example For example, isotretinoin, which is used to treat acne, belongs to category X. It can cause abnormalities in the central nervous system, the face, and various organs such as cardiovascular system in the fetus. Currently, there is no classification for the safe use of drugs during pregnancy in China. For drugs that are definitively teratogenic in animals, Chinese drug instructions are labeled “prohibited for pregnant women”; for drugs that are not definitively teratogenic, Chinese drug instructions are standardized to “use with caution in pregnancy”. This broad standard often conflicts with the FDA’s classification. For example, the FDA classifies the antibiotic metronidazole vaginal effervescent tablets, which are commonly used in obstetrics and gynecology during pregnancy, as Class B and can be used during pregnancy, while the Chinese instructions are labeled as prohibited. When such a conflict arises, the best solution is to use the drug under the guidance of a physician and with reference to more new clinical data from home and abroad. Principles of safe drug use during pregnancy No drug is absolutely safe for the fetus. Consider using a drug only when the benefits to the mother outweigh the risks to the fetus, and if possible, avoid using any drug during the first 3 months of pregnancy. When it is necessary to use it, choose a safe drug that has been in clinical use for as long as possible. When using drugs, choose the smallest effective dose and the shortest effective course of treatment. The emphasis on “long duration of clinical use” is due to the fact that the effects of the drug on the fetus may be different from those expected to occur in the mother, and that such differences may only be detected during long-term clinical use. For example, the drug “Reactive Stop” was used as an antiemetic in early pregnancy when it was first marketed, but its effect on the fetus was to cause multiple fetal limb malformations. “It was only after the birth of a group of babies with hands and feet shaped like seals that the teratogenic effect of this drug was discovered. The emphasis on “safe” means to use drugs that are classified by the FDA as Class A or B for safety during pregnancy. Drugs with suspected or proven teratogenic effects in humans: amantadine, ribavirin, acarbose, rosiglitazone, nateglinide, warfarin, ergotamine, lithium, ketorolac, testosterone, hexestrol, isotretinoin, retinoic acid, isotretinoin, adapalene, ghosts, all antineoplastic drugs used for radiation and chemotherapy, and live attenuated vaccines for measles, rubella, and mumps (these live attenuated vaccines have no effect on healthy young children and adults, except for the possible teratogenic effect on embryos conceived by pregnant women). Allergic dermatitis or rhinitis can be treated with antihistamine allergy medications during pregnancy, of which paracetamol and diphenhydramine are class B drugs that have been in clinical use for a long time and are relatively safe during pregnancy. The box says “contraindicated: not yet clear” which means there is no experimental data, Chinese medicine is also a medicine, there is no safety data, there is a safety risk, can not be understood as harmless to pregnant women. Antibiotics that can be used during pregnancy: cephalosporins, penicillins, azithromycin, clindamycin. Antibiotics to be avoided during pregnancy: tetracyclines, doxycycline, clarithromycin, etoricoxib, quinolones (e.g. ciprofloxacin), aminoglycosides (e.g. amikacin).