Prevalence of Group B Streptococcus Colonization in Subsequent Pregnancies of Group B Streptococcus-Colonized versus Noncolonized Women

Objective To determine whether group B Streptococcus (CBS)-colonized pregnant women have an increased prevalence of CBS colonization in subsequent pregnancies. Study Design This retrospective cohort study compared the prevalence of GBS colonization in initial and subsequent pregnancies of 158 women with two or more deliveries at a Midwest institution since the initiation of universal screening for CBS. Results The CBS colonization rate in index pregnancies was 20%. Colonization rate in subsequent pregnancies for initially GBS-colonized women was 42% compared with 19% for women who were not colonized with GBS in the index pregnancy (p = 0.009). The relative risk for CBS-colonized women to be CBS-colonized in subsequent pregnancies was 2.2 (confidence interval = 1.3 to 3.8). Conclusion Previous GBS colonization is a risk factor for CBS colonization in subsequent pregnancies. Consideration of intrapartum chemoprophylaxis in women with a history of CBS colonization, assuming current colonization status is unknown, warrants further investigation.