Hépatite B et grossesse. Partie 1. Treize questions pratiques en période anténatale

In France, the prevalence of chronic hepatitis B is about 1% in pregnant women (usually asymptomatic carriers of HBsAg). The risk of maternal-fetal transmission of hepatitis B is particularly high when viral load measured by PCR is higher in mothers (above 7 log) or HBeAg is present. In case of maternal-fetal transmission of hepatitis B, the risk to the newborn of developing subsequent chronic hepatitis B is very high (90%), with long-term complications such as cirrhosis and hepatocellular carcinoma. The prevention of maternal-fetal transmission is based on systematic testing for hepatitis B during pregnancy, followed by serovaccination of the newborn at birth. If necessary, amniocentesis can be realised but will avoid the realization of a transplacental gesture. In case of high viral load, the establishment of a maternal antiviral treatment with lamivudine or tenofovir from 28 SA can further reduce the risk of transmission. Given the low resistance it induces, tenofovir should be used preferentially.