The 2015 edition of the Guidelines for the Prevention and Treatment of Chronic Hepatitis B has just been released at the 2015 Annual Meeting of the Chinese Medical Association’s Division of Infectious Diseases and the Chinese Medical Association’s Division of Hepatology, and this is a brief explanation of the fertility issues related to chronic hepatitis B virus infection. Hepatitis B exacerbations during pregnancy: Recommendation 18: Patients with hepatitis B exacerbations during pregnancy with mildly elevated ALT can be closely observed, and those with more severe liver lesions can be treated with tenofovir or telbivudine antiviral therapy (A1) after full communication with the patient and weighing the pros and cons. Management of unintended pregnancy during antiviral therapy: Recommendation 19: In patients with unintended pregnancy during antiviral therapy, termination of pregnancy is recommended if interferon therapy is applied (B2). If pregnancy level B drugs (tenbivudine or tenofovir) or lamivudine are used, treatment may continue; if entecavir and adefovir are used, treatment should be continued with tenofovir or tenbivudine instead of termination of pregnancy (A1). Recommendation 20: To further reduce mother-to-child transmission of HBV, tenofovir, telbivudine, or lamivudine may be given starting in the 28th week of gestation in order to further reduce HBV mother-to-child transmission, with HBV DNA load greater than 2×106IU/ml in mid- to late-pregnancy, with adequate communication and weighing the pros and cons. For male patients on antiviral therapy for fertility: male patients on interferon therapy should be considered for fertility only 6 months after discontinuation; male patients on antiviral therapy with NAs (entecavir, tenofovir, adefovir, telbivudine, lamivudine), there is no evidence of adverse effects of NAs treatment on sperm and fertility can be considered with adequate communication with the patient. Annex: There are several approaches to classify the safety of drugs for pregnant women during pregnancy. Among them, the standards developed by the U.S. Food and Drug Administration, which are clear in meaning and scientific and objective, and therefore widely accepted by physicians in various countries, classify the safety of drugs into five categories: A, B, C, D and X. Some drugs have two different risk levels, one for the commonly used dose level and the other for the extraordinary dose level. The five classes of classification criteria are described below. Class A, which has not been shown to be dangerous to the fetus in early pregnancies with controls (and has no evidence of danger in intermediate or late pregnancies) and may cause minimal harm to the fetus. Category B No risk to the fetus has been demonstrated in animal reproduction tests, but there is no control group of pregnant women, or side effects (less severe than sterility) have been demonstrated in animal reproduction tests, but the side effects are not certain in control groups of early pregnant women (and there is no evidence of risk in mid- and late-term pregnancies). Class C Side effects on the fetus (teratogenic or embryonic lethal or otherwise) have been demonstrated in animal studies, but there are no controls in women or no available information in women and animal studies. Drugs should be given only when the balance of benefits to the fetus outweighs the harms. Category D Positive evidence of risk to the human fetus, but although harmful, the benefit to the pregnant woman needs to be certain before it is given (e.g., for life-threatening or serious illness where safer drugs cannot be applied or where the drug is ineffective). Class X. The drug has been shown in animal or human studies to cause fetal abnormalities or is known to be dangerous to the fetus based on human experience, harmful to humans or to both, and the risks of its use in pregnant women clearly outweigh any beneficial effects. This drug is contraindicated in women who are or will be pregnant. Among the nucleoside analogs for hepatitis B antiviral therapy, telbivudine and tenofovir are pregnancy category B drugs, while lamivudine, adefovir, and entecavir are pregnancy category C drugs. Among them, although lamivudine is a class C drug, a large amount of clinical data confirm that it is not only effective in preventing intrauterine transmission of hepatitis B virus and mother-to-child transmission of HBV after delivery, but is also safe for both mother and baby.