Management of group B streptococcal disease in pregnancy

GBS is a bacterium that may cause devastating disease. The puzzle of GBS management revolves around the fact that the organism colonizes 15-30% of women, yet produces infection in only 1-3% of the women who are colonized. Neonatal infection is acquired from the maternal genital tract. It ascends across the cervix into the amniotic cavity and also may be acquired during delivery. Manifestations of disease in the fetus and neonate may be out of proportion to those in the mother. Treatment strategies involve the screening all pregnant women with cultures at 26-28 weeks' gestation and rapid tests at the time of labor. Rapid testing has not proven successful, although current research should provide effective and sensitive rapid tests by the end of the decade. Once a woman is known to be GBS positive in labor, there are two options. Most investigators recommend giving chemoprophylaxis only to women who are at high risk for GBS infection--women with preterm labor, ruptured membranes for longer than 12-18 hours, or intrapartum fever higher than 37.5 degrees C. Others advocate treating all GBS carriers regardless of risk status. Treatment of mothers in labor eradicates vaginal carriage of GBS, though it does not eradicate GBS from the lower digestive tract. Intrapartum chemoprophylaxis decreases the incidence of neonatal colonization and significantly decreases the risk of infant disease. In the future, GBS infection probably will be prevented with immunoprophylaxis and vaccination.