The human embryo is a very delicate “species” and its development is influenced by many environmental factors in addition to the genetic material of its parents. Genetic factors, air pollution, food contamination and other environmental factors are beyond the control of ordinary people, while drugs, smoking, alcoholism and other factors, to some extent, can be controlled. Here the focus is on the effect of drugs on the fetus. And when it comes to the use of medication during pregnancy, two public cases have to be mentioned: one is the seal child malformation and the other is tetracycline teeth. Tetracycline antibiotics (including tetracycline, oxytetracycline, gentamycin, etc.) are inexpensive and of low toxicity, but unfortunately if a pregnant woman takes a tetracycline drug during the period of mineralization of the fetus’s tooth development, the drug can be bound into the fetus’s dental tissues, staining the teeth and causing enamel hypoplasia. China to the mid-1970s to notice this problem, and now we see tetracycline teeth are mostly “after 60” or “after 70” people. This medication mistake has caused pain for countless people, but fortunately dentistry can fix it, albeit at a high price. A small, insignificant pill can cause large or small deformities or abnormalities, bringing shadows to the baby’s life, or even so serious that it does not have a chance to come into the world, so the issue of medication during pregnancy is very important. Principles of maternal medication 1, there must be clear indications to avoid unnecessary medication. 2, do not self-medication, must be under the guidance of the doctor to use drugs. 3, can use a kind of drug, do not use two or more kinds of drugs. 4, with the efficacy of the old drugs, do not use the new drugs on the fetus is not sure whether the adverse effects of the new drugs. 5, can use a small dose, do not use a large dose. 6, strict control of drug dosage and duration, can stop the drug in time. 7, if the condition allows, early pregnancy as far as possible not to use drugs, postponed to the middle of pregnancy. 8.If the condition is so special that drugs harmful to the fetus must be used in early pregnancy, termination of pregnancy needs to be considered. Harmfulness level of drugs to the fetus How to evaluate the harmfulness level of drugs to the fetus? The U.S. Food and Drug Administration (FDA) categorizes drugs as A, B, C, D, or X in terms of their harm to the fetus. It is generally recognized that drugs of classes C, D, and X should not be used in the first 12 weeks of pregnancy. Grade A After clinical control studies, there is no information to confirm that the drugs have harmful effects on the fetus in the early and mid-late stages of pregnancy, and the possibility of harm to the fetus is minimized, which is a non-teratogenic drug. Such as appropriate amounts of microorganisms and trace elements. Grade B Not shown to be harmful to the fetus by animal experimental studies, but no clinical control experiments, no evidence of harmful effects in humans, and can be used under the observation of a physician, e.g., penicillin, erythromycin, digoxin, and insulin. Class C Drugs that have been shown by animal experiments to have adverse effects on the fetus. In the absence of controlled clinical trials, they can only be used with caution when the benefits of the drug to the pregnant woman, the potential benefits to the fetus, and the harm to the fetus are adequately weighed, e.g., gentamicin, iproniazid (psychiatric drug), isoniazid (anti-tuberculosis drug). Grade D Drugs with sufficient evidence of harm to the fetus should be considered for use only when the life of the pregnant woman is in danger or when she is suffering from a serious disease and other drugs are ineffective, e.g., streptomycin sulfate. Class X Drugs that have been proven in animal and human experiments to cause fetal malformations are prohibited for use during pregnancy or in women who may become pregnant. Such as methotrexate, hexestrol, etc.. In addition to the need for special caution in the use of medication during pregnancy, during pregnancy or even 3 months prior to pregnancy should be detoxification, quit smoking, quit drinking, less exposure to radiation-intensive electronic products. Drugs and tobacco are street rats, and their harmful effects on the mother and fetus are self-evident. Alcoholism is also harmful to the fetus, as evidenced by the fact that the descendants of Li Bai, who drank ten thousand bottles of wine, are not as powerful as the descendants of Confucius. As for the popularity of women’s cell phones and tablet computers and other electronic products, in bringing convenience and fashion at the same time, are different degrees of radiation, for the sake of the baby, or try to stay away.