Can hepatitis B virus cause fetal malformations?

Hepatitis B virus itself usually does not directly cause fetal malformations. Its primary risk lies in transmitting the virus to the fetus, rather than directly causing structural or developmental abnormalities in fetal organs. A detailed analysis is as follows:

The transmission routes of hepatitis B virus include mother-to-child transmission. If effective preventive measures are not taken during pregnancy, the virus may be passed to the fetus via the placenta, or through exposure to maternal blood or bodily fluids during delivery. However, current research indicates that the hepatitis B virus does not integrate into the fetal germ cells or somatic cell genomes, nor does it directly interfere with organ differentiation and development in the fetus. Therefore, it does not directly lead to structural abnormalities such as limb deformities or internal organ defects.

Nonetheless, hepatitis B infection may indirectly affect pregnancy. If a pregnant woman develops severe liver damage due to hepatitis B infection—such as fulminant hepatitis—this could lead to maternal metabolic disturbances, hypoxia, and other complications, which in turn may impair normal fetal growth and development, increasing risks such as intrauterine growth restriction or preterm birth. However, these outcomes are not classified as fetal malformations.

To reduce the risk of mother-to-child transmission, pregnant women who are hepatitis B surface antigen positive should receive appropriate interventions under medical guidance, including standardized antiviral therapy during pregnancy and timely administration of hepatitis B immunoglobulin and the first dose of hepatitis B vaccine to the newborn after birth. With scientifically guided preventive measures, the risk of fetal hepatitis B infection can be reduced to a very low level, while also minimizing indirect adverse effects on fetal health caused by maternal illness.