Perinatal transmission is the most common mode of HBV transmission worldwide; However, the maternal screening programs and universal vaccination in newborns with active and passive immunoprophylaxis have dramatically reduced HBV transmission rates.
Risk of chronic infection
The risk of progression to chronic HBV infection is inversely proportional to the age at which the infection was acquired. Without immunoprophylaxis, up to 90% of infants born to hepatitis B e antigen (HBeAg)-positive mothers become HBV carriers. In comparison, 20% to 30% of children infected between age 1 year and 5 years, and fewer than 5% of immunocompetent adults, become HBV carriers. If the mother is positive for both HBsAg and HBeAg and her baby does not receive immunoprophylaxis, the risk of the baby developing chronic HBV infection by age 6 months is 70% to 90%. Of those exposed in early childhood, 28.8% are HBsAg positive by age 4 years. These data underscore the need for early vaccination.
Family physicians encounter diagnostic and treatment issues when caring for pregnant women with hepatitis B or C and their newborns. When hepatitis B virus is perinatally acquired, an infant has approximately a 90 percent chance of becoming a chronic carrier and, when chronically infected, has a 15 to 25 percent risk of dying in adulthood from cirrhosis or liver cancer. However, early identification and prophylaxis is 85 to 95 percent effective in reducing the acquisition of perinatal infection. Communication among members of the health care team is important to ensure proper preventive techniques are implemented, and standing hospital orders for hepatitis B testing and prophylaxis can reduce missed opportunities for prevention. All pregnant women should be screened for hepatitis B as part of their routine prenatal evaluation; those with ongoing risk factors should be evaluated again when in labor. Infants of mothers who are positive for hepatitis B surface antigen should receive hepatitis B immune globulin and hepatitis B vaccination within 12 hours of birth, and other infants should receive hepatitis B vaccination before hospital discharge. There are no effective measures for preventing perinatal hepatitis C transmission, but transmission rates are less than 10 percent. Perinatally acquired hepatitis C can be diagnosed by detecting hepatitis C virus RNA on two separate occasions between two and six months of age, or by detecting hepatitis C virus antibodies after 15 months of age.
Source: ccjm.org and aafp.org