In reproductive medicine clinics, a significant proportion of couples come to consult about the use of medication before and after pregnancy. For example, pregnancy with failed contraception using emergency contraceptives, using anti-cold medication because of mistaking early pregnancy reaction for cold symptoms, using anti-infection medication because of frequent urination after pregnancy mistaking it for urinary tract infection, etc. If the following information is known, I believe that couples can calmly start analyzing instead of heatedly discussing malformations, abortions, etc. 1) Among all factors that cause fetal malformation, drug factor is less than 1%; 2) Western drugs have a strict classification of drugs used during pregnancy (A/B/C/D/X), class A such as many vitamins and class B such as penicillin cephalosporins have not been reported to be teratogenic to human embryos so far; 3) Within 2 weeks of fertilization, the effect of drugs on embryos is “all or nothing “(i.e., if the embryo is affected, it is not viable, and if the embryo is viable, the drug has no effect on the embryo). For women with regular menstruation, ovulation is easy to determine and some women will also have significant ovulation pains. The 2-week period of fertilization is easy to calculate and, when combined with the duration of action of the drug used (the pharmacokinetic half-life on the drug insert provides an important reference), a preliminary determination can be made as to whether the drug will have an effect on the developing embryo. For women with irregular menstrual periods, it is necessary to consult a reproductive medicine doctor to calculate this, or to use ultrasound or blood tests to make a determination. All pregnant women who have used drugs before or after pregnancy are advised to intensify their prenatal checkups and diagnosis. Do not blindly choose abortion as a method of disposal, as endometrial damage or secondary pelvic infection due to abortion procedures is now one of the main factors of infertility.