Patients with chronic hepatitis B who are on antiviral therapy often come for consultation because of pregnancy problems, and the relevant issues are discussed below. First, the safety of interferon using interferon treatment of chronic viral hepatitis should be clear: interferon, in addition to anti-HBV, has the role of inhibiting cell proliferation, clinical also as anti-tumor biotherapy. We know that the embryo is developed into a fetus from a clump of cells through numerous divisions and reproduction, so young men and women who use these drugs to treat hepatitis cannot get pregnant, and patients who need to get pregnant need to stop taking the drug for 3 months before conception. Second, the instructions of nucleoside analogues stipulate that a standard new drug must have done animal teratology tests before it can be approved for clinical use, so the instructions of imported drugs are marked with the effect on the embryo, divided into three levels: A (safe), B (animal tests without embryotoxicity and teratogenicity, no research on humans) and C (animal tests with embryotoxicity and teratogenicity). Based on preclinical testing of these drugs, the FDA classified entecavir, adefovir, and lamivudine (which later had additional information suggesting that it had been changed to Class B) as Class C, with low safety to embryos; and telbivudine and tenofovir as Class B, with no significant problems found in animal testing, but no human clinical testing done to ensure safety. According to the moral ethics to humans also impossible to do clinical trials, so currently there is no class A drugs. Therefore, the instructions of nucleoside analogs are written that pregnancy is not possible during taking the drugs. Third, nucleoside drugs on embryonic effects of test results lamivudine according to the body surface area of 130 times the adult amount, used in mice does not affect fertilized egg implantation, embryonic development and growth; fed to mice with a dose of 2 mg per gram of body weight does not have genotoxicity; microbial screening test is not teratogenic, but there is a very weak teratogenicity to human lymphocytes cultured in vitro. Tenofovir fed to neonatal and infant rhesus monkeys at 18-fold dose was not toxic for 3 months; beyond 4 months growth restriction, phosphate-deficient chondropathy and abnormal renal tubular function were observed, but all lesions recovered after discontinuation of the drug. The birth defect rate for general pregnancy monitored by the Centers for Disease Control in the United States is 2.72%. The African Anti-Immunodeficiency Virus (HIV) Pregnancy Registry, which also registers the fetal teratogenicity of anti-HBV drugs, has a neonatal defect rate of 2.9% for lamivudine and 2.3% for tenofovir when pregnant women start lamivudine in early pregnancy, with corresponding data of 2.6% and 1.5% for starting both drugs in mid- to late-term, which are not significantly different from the CDC data. No data are available for both pregnancy registries for tenbivudine on the fetus. To date, there is considerable clinical experience both domestically and internationally, and there is no evidence of teratogenicity or adverse effects on pregnancy with lamivudine or tenofovir during pregnancy. Moreover, foreign literature reports that hundreds of thousands of people are now using lamivudine, and some of these patients taking the drug have accidentally become pregnant accidentally, and no reports of neonatal malformations have been seen. Fourth, what should specialists tell their patients in the face of questions, I often tell my patients in the clinic: First of all, they should comply with the drug instructions, and they should stop taking nucleoside drugs for six months (at least 3 months) before considering pregnancy. If you are older or have an unplanned pregnancy and do not want to terminate it, you need to take part of the risk yourself. Although there are some clinical data showing that the teratogenicity of lamivudine, telbivudine and tenofovir may be very low, as a physician, you cannot go against the regulations of the drug instructions.