[Streptococci group B and pregnancy. Need for routine check-ups?].

Group B streptococci are a major cause of perinatal infections and affect 1-5 infants out of every 1,000 live births. Maternal vaginal colonization with these bacteria is common (5-25%), and has been associated with late abortions, foetal growth retardation, early rupture of membranes and premature delivery. Colonization with group B streptococci may be observed in more than 70% of neonates born to mothers with the bacteria in their vaginal tracts at delivery. A high number of bacteria in the maternal urogenital tract during pregnancy may predispose to early-onset disease in neonates. The estimated attack rate in colonized neonates is 1-2%. A high specific IgG antibody concentration in the mother may protect the infant, but probably not before 32 weeks of gestation. Colonized women who are unable to produce such antibodies risk having affected offspring. Neonatal infection with group B streptococci frequently results in death or permanent neurologic morbidity; especially from the early-onset type (case-fatality more than 50%) which is most often vertical transmitted. Four cases with early-onset disease illustrate the severity of perinatal group B streptococcal infections. The severity and outcome of the disease may be moderated by screening for group B streptococci during late pregnancy. This screening must be combined with special attention to irregularities in pregnancy or perinatal complications.