Prevention of Hepatitis B Virus Mother-to-child Transmission by Serovaccination.

This monocentre, observational study will include pregnant women whom HBV-DNA is \> 105 IU/mL. HBV MTCT rates will be evaluated, according to the level of HBV-DNA in the women during the last three months of pregnancy and at childbirth (between 105 and 108 IU/mL, or \> 108 IU/mL), and according to the clinical practices of serovaccination in the participating center. The evaluation will be based on the rate of HBsAg positivity in infants at 9 months, despite a correct immunization at birth. The rate of detectable HBV-DNA will be also evaluated in infants at the same date.