[Hepatitis B and pregnancy. Part 2. Nine practical issues about delivery and neonatal care].

In France, the hepatitis B maternal-fetal transmission prevention strategy is based on serovaccination at birth. Serum therapy is to inject 30IU/kg of anti-HBs specific immunoglobulins of human origin in the first hours of life, which in practice corresponds to 1ml or 100IU. Vaccination should also be performed during the first hours of life, and a new injection should be performed at 1month and 6months. In infants less than 32weeks and/or less than 2kg, lower vaccine response leads to prescribe an additional injection at 2months. This serovaccination reduces the risk of mother to child transmission from 57 to 4 %. The failure risk factors of serovaccination are high maternal viral load (greater than or equal to 7 log) and/or the presence of HBeAg. The delivery route does not change the risk of maternal-fetal transmission of hepatitis B when serovaccination at birth was well conducted. Likewise, breastfeeding does not change the risk of maternal-fetal transmission of hepatitis B after serovaccination. It is recommended by WHO. During labor, the pH in utero should be done only when strictly necessary, the published data do not allow to conclude on the risk of transmission.