It is estimated that 350 to 400 million individuals worldwide are chronically infected with hepatitis B virus (HBV). In regions of high endemicity, many of these are females of reproductive age who are an important source for perinatal transmission. There are a number of issues specific to the women of childbearing age who have chronic HBV infection, including the safety of antiviral therapy during pregnancy and breast-feeding, the changes in the immune system during pregnancy and postpartum that may impact on the natural history of HBV, and the emerging role of antivirals to reduce perinatal transmission of HBV. For women in their reproductive years who require treatment, many of the available antivirals have not been studied in pregnant or breast-feeding women and their use requires the development of a carefully considered strategy, considering the impact of both the disease and treatment on the mother and fetus/infant. The purpose of this article is to (1) review data regarding the mechanisms and timing of perinatal HBV infection; (2) review data on interventions, particularly antiviral therapy, to reduce perinatal transmission beyond the protection afforded by hepatitis B immunoglobulin and vaccination; (3) summarize the immunological changes associated with pregnancy and the potential effect these may have on the natural history of HBV infection; and (4) summarize the information currently available for antiviral therapy available for HBV treatment, focusing specifically on safety data pertaining to reproduction, pregnancy, and breast-feeding. TARGET AUDIENCE: Obstetricians Gynecologists and Family Physicians. LEARNING OBJECTIVES: After completing this CME activity physicians should be better able to classify the interventions to reduce mother-to-child transmission of hepatitis B including antivirals, caesarean section, hepatitis B immunoglobulin and hepatitis B vaccine, assess the immunological changes associated with pregnancy and the potential effect this may have on the natural history of HBV infection and apply the information currently available for antiviral therapy licensed for HBV treatment, focusing specifically on safety data in pregnancy and during breastfeeding.