The prevalence of HBsAg carriage in pregnant women varies in France, according to the native country, with highest rates in those originating from sub-Saharan Africa and Asia (5 to 8 % in Parisian area). The level of HBV-DNA varies according to HBe status and geographical origin, and is strongly predictive of the risk of HBV mother-to-child transmission (MTCT). It has been shown that the rate of vertical transmission (Chinese study by Yuan J et al) was 0 % in newborns to mothers whom HBV-DNA was < 105 copies/mL and up to more than 40 % in newborns to mothers with high viral loads > 108 copies/mL, despite HBIg and vaccine at birth. Thus, data are needed concerning the current practices about the prevention of HBV MTCT in France, and their results.

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.

Inclusion Criteria:

• Pregnant woman
• whom HBs Ag +
• whom HBV-DNA >105 IU/mL

Exclusion Criteria:

• Women who have to be treated for HBV hepatitis, (AST/ALT >2 ULN without any explanation, liver biopsy performed before pregnancy showing hepatitis requiring initiation of treatment)

This monocentre, observational study will include pregnant women whom HBV-DNA is > 105 IU/mL and who are not currently treated for HBV hepatitis.