I. Use of drugs at different times 1. Within 3 weeks of menopause: safer. The effect of the drug is “all or nothing”. 2, 3-8 weeks of pregnancy: high sensitivity period. Drugs can cause malformation but not necessarily spontaneous abortion, such as vaginal bleeding, should not keep the baby. 3.8 weeks of pregnancy-5 months: medium-sensitive period. The effect of drugs is more difficult to predict, it is recommended to do ultrasound and amniocentesis in time. 4.After 5 months of pregnancy: hypoallergenic period. No malformation but may have local developmental abnormalities. Second, drug safety classification 1, safety: general dose of vitamins. Relative safety: some antibiotics, antipyretic and analgesic drugs, cardiac glycosides, short-acting adrenocorticotropic hormone. 3, weighing the use of: antiviral drugs, some antipyretic analgesics, some antiepileptic drugs, sedatives, cholinergics, vasodilators, adrenocorticotropic hormones. 4, must not be used: aminoglycosides, antineoplastic drugs, most antiepileptic drugs, sedative-hypnotic drugs, diuretics. 5, can not be used: ACEI class, androgens, antitumor drugs. The above is just an overview, specific problems need to be treated specifically, it is recommended to consult a physician or pharmacist.