Risk of Recurrence of Group B Streptococcus in Subsequent Pregnancies

Abstract

INTRODUCTION: Reports have shown that up to half of women will be recolonized with group B streptococcus (GBS) in a subsequent pregnancy. A systematic review and meta-analysis was conducted to investigate the prevalence and recurrence risk of GBS colonization in a subsequent pregnancy and to determine clinical characteristics that increase the probability of recolonization. METHODS: A search was conducted of the existing literature (PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov) from inception to September 2014. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines were used. RESULTS: Five cohort studies were identified that analyzed 1,150 women in a subsequent pregnancy. The prevalence of recurrent GBS was 44.5% (512/1,150). Colonization with GBS in the index pregnancy (compared with women who were not colonized) was associated with a higher rate of recurrent colonization in a subsequent pregnancy (three studies: 50.2% compared with 14.1%, pooled fixed-effects odds ratio [OR] 6.05, 95% confidence interval [CI] 4.84–7.55, P<.01, I2=24%). Among all patients colonized with GBS, heavy colonization (either by bacteriuria or more than 80 colony-forming units) was associated with increased risk of recurrence (four studies: 52.0% compared with 45.1%, pooled fixed-effects OR 1.54, 95% CI 1.02–2.31, P=.04, I2=0%). Subgroup analysis showed no effects of pregnancy interval less than 12 months, body mass index (calculated as weight (kg)/[height (m)]2) greater than or equal 30, primiparous in subsequent pregnancy, or race or ethnicity. CONCLUSION AND IMPLICATION: Colonization with GBS during pregnancy is associated with a high rate of recurrence in the next pregnancy. A higher rate of recurrence is noted in women considered to have heavy genital tract colonization.