Mother to newborn and infant transmission of hepatitis B infections.

A review of maternal transmission of HBV infections revealed that transmission rates are high in many countries in Asia, due mainly to the high prevalence of carriers and high HBeAg rates in these carriers. Transmission can occur in the anteparturn, intrapartum and postpartum periods. About 90% occurs at the time of birth, and 5-10% are the result of in-utero infection. 90% of newborns infected at this age become chronic carriers. Maternal transmission is responsible for about 40-50% of the pool of carriers in Asia, for clustering of carriers, chronic liver disease and primary hepatocellular carcinoma, and is a continuing source of the virus. The role of the HBeAg, anti-HBe and changing patterns in the ability of infected newborns and young females to respond to HBV infections is also discussed.