Chronic hepatitis B virus (HBV) infection affects about 350 million individuals worldwide. Perinatal transmission is a common mode of HBV transmission. Without prophylaxis the risk of mother-to-child transmission is very high and it depends on the HBeAg status of mothers, being 85%-90% for HBeAg-positive mothers, and 32% for HBeAg-negative mothers. Maternal screening programs aimed at identifying HBsAg-positive mothers should be part of pregnancy routine examinations. Once HBsAg-positive mothers are identified, their babies receive passive-active immunoprophylaxis at birth, this reduces the risk of vertical HBV transmission from 90% to 5-10%. The present review aimed to show the peculiar and sometimes controversial aspects which concern both the mother and the fetus in the case of HBV infection in pregnancy, including the effect of pregnancy on HBV infection and of HBV infection on pregnancy; the potential viral transmission from mother to newborn; and prevention of mother-to-child transmission through antiviral drugs, and the type of antiviral drug to use considering their efficacy and potential teratogenic effect.