A. Four principles of safe maternal medication The mother-to-be should not be careless with medication during pregnancy when she is accidentally sick, and the random use of medication will have adverse effects on the fetus, if not treated with medication, and easily affect the growth and development of the fetus. Therefore, the safe use of medication during pregnancy is most important. These unfortunate, have you heard of? 1, pregnant women worry about the impact of drugs on the fetus, delaying the treatment of diseases, affecting the growth and development of the fetus; 2, pregnant women are not careful with drugs, resulting in the need to terminate pregnancy; 3, pregnant women are not careful with drugs, giving birth to deformed children; maternal diseases, which can endanger the embryo in the womb, the fetus, and maternal drug treatment can not only make the disease as soon as possible to heal, but also benefit the fetus. However, it is inevitable that the drugs used may have adverse effects on the embryo and fetus. In order to avoid these unfortunate occurrences, please note that the safety of maternal medication is most important! Understanding maternal physiological characteristics is the basis for safe medication use The pre-fertilization period refers to the period from the fertilization of the egg to the time when the fertilized egg is deposited in the endometrium. During this period, the fertilized egg is not yet in direct contact with the maternal tissue and is still in the secretion of the fallopian tube or the uterine cavity, so maternal medication during this period has little effect on it. After the fertilized egg is laid until about 12 weeks, it is an important stage for the embryo and fetal organs to be highly differentiated, rapidly developing and constantly forming. If pregnant women apply drugs during this period, their toxicity can interfere with the normal differentiation of embryonic and fetal tissue cells, and as pregnancy progresses, they may cause malformation of a certain part of the tissue or organ. Therefore, 12 weeks of gestation is the most sensitive period for drug teratogenesis. After the fourth month of pregnancy, as most of the fetal organs have been formed, the sensitivity of drug teratology is obviously weakened, but the reproductive system may still be affected to different degrees, while the nervous system continues to differentiate and develop during the whole pregnancy, therefore, pregnant women should be cautious in using drugs during the middle and late pregnancy and maternity period. Second, mastering the principles of maternal medication is the key to safe medication The general principle of maternal medication is to choose medication according to scientific principles and use it rationally. The use of drugs should be the smallest effective dose, the shortest effective course of treatment as a guideline. If the condition is not necessary, avoid the use of drugs in early pregnancy as much as possible; when local drugs can be used, avoid systemic drugs as much as possible. The specific drug selection is based on the drug classification issued by the US Drug and Food Administration. This classification is based on the different teratogenic conditions of drugs for humans, and the drugs are classified into five levels: A class drugs are safe and harmless to embryo and fetus, such as sodium penicillin and moderate amount of vitamins; B class drugs are safer and basically harmless to fetus, such as erythromycin and paracetamol; C class drugs are only proven to be harmful in animal experimental studies, but not in Class C drugs have only been proven to be harmful in animal studies, but not in human studies. Class D drugs have definite evidence of fetal harm and should not be considered unless there is a compelling reason to use them, such as streptomycin sulfate, which can cause damage to the 8th pair of brain nerves and hearing loss. To prevent drug-induced fetal malformations, it is better not to use Class C, D, or X drugs during the first trimester of pregnancy. In case of maternal emergencies, we should also be cautious and recommend the use of class A and B drugs that have been proven to be non-teratogenic for many years under the guidance of experienced clinical experts.