Mechanisms and Prevention of Vertical Transmission in Chronic Viral Hepatitis.

Vertical transmission (VT) is the primary route of transmission of viral hepatitis in children. The rate of VT ranges from 1-28% with hepatitis B virus (HBV) and 3-15% with hepatitis C virus (HCV). VT for both viruses can occur during the intrauterine or peripartum period. VT of HBV primarily occurs by intrauterine transmission (IUT). Hepatitis B surface antigen is unable to cross the placenta and, therefore, relies on processes like transplacental leakage, placental infection, cellular transmission by peripheral blood mononuclear cells, and germline transmission. HCV can also infect the fetus by IUT. Both viruses also have the potential for transmission during delivery, when there is increase chance of maternal-fetal blood exposure. HBV and HCV share some common risk factors for VT, including maternal viral load, human immunodeficiency virus co-infection and neonatal sex. Prevention of VT differs greatly between HBV and HCV. There are several alternatives for prevention of HBV VT, including antiviral medications during the third trimester of pregnancy and HBV vaccine, as well as hepatitis B immunoglobulin administration to infants post-partum. In contrast, there are no preventative interventions available for HCV. Despite these differences, the key to prevention with both viruses is screening women prior to and during pregnancy.