Hepatitis B infection during pregnancy presents a unique set of management issues. Aspects of care that must be considered include maternal and fetal effects of hepatitis B, effects of pregnancy itself on the course of hepatitis B infection and its complications, treatment of hepatitis B during pregnancy and prevention of perinatal infection. There are insufficient studies to date regarding these concerns; most are from the Far East, and many have important limitations, but some have yielded valuable data. Pregnant women with acute hepatitis B virus (HBV) infection typically have a course not very different from that in the general adult population, but the risk of transmission of HBV to neonates increases the later in gestation the acute infection occurs. Chronic HBV infection is usually mild in pregnant women, but may flare shortly after delivery. The risk of perinatal transmission is highest in women with high levels of viraemia; this may be a factor in the small but reproducible failure rate of current immunoprophylaxis strategies. Obstetrical policies must be assessed with respect to detection of maternal infection and liver disease, as well as with respect to perinatal transmission risk. In addition to the usual issues of drug efficacy and safety in the affected individuals, effects on the developing fetus must be considered. This paper reviews the current experience in each of these areas, and highlights the need for further investigation into this critical but often underestimated topic.