Diagnosis of HBV infection among pregnant women is necessary for the child protection against infection with this virus as well as further diagnosis and therapy of the mother. HBV infection may affect the increased incidence of early deliveries, lower Apgar scores in newborns as well as a greater risk of developing diabetes or antenatal haemorrhage in pregnancy. On the other hand, increased concentrations of adrenal corticosteroids and estrogens during pregnancy may be responsible for increase of HBV viral load. The risk of infection to the unborn fetus is minimal, but it increases when childbirth is carried in the natural way. The risk is particularly high among mothers with high viral load and present HBe antigen. In order to protect the fetus from infection it is recommended to complete pregnancy by cesarean section, and additionally provide active-passive prophylaxis immediately after childbirth. None of the antiviral drugs used in the treatment of HBV is authorized by the FDA for use in pregnant women. However, data collected on some of these drugs administered in the past to HIV and HBV-infected females which during pregnancy became pregnant, demonstrated frequency of congenital defects on the level similar to general population of newborns in Poland. Concluding, pregnancy in females with high HBV viral load and advanced liver disease should be preceded if possible by an antiviral treatment, because of the high rate of complications. Women with low viral load and slight liver damage, can be treated after birth, but appropriate newborn prophylaxis against HBV infection should be provided immediately.