Efficiency of Screening for the Recurrence of Antenatal Group B Streptococcus Colonization in a Subsequent Pregnancy: A Systematic Review and Meta-analysis with Independent Patient Data

Objective The objective of this study was to evaluate the risk of recurrent group B streptococcus (GBS) colonization in a subsequent pregnancy and to assess clinical characteristics that influence this risk. Study Design A systematic review and meta-analysis was performed. Databases were searched from inception through June 2015 using PubMed, Embase, Scopus, Central, and ClinicalTrials.gov. Studies were eligible if they assessed antenatal GBS colonization in two successive pregnancies. The quality of included studies was evaluated. Independent patient data was requested from the authors of the included trials. Unadjusted odds ratios (OR) were pooled using the Mantel-Haenszel fixed effect model. Results In the five studies identified, two studies lacked a nonexposed cohort. GBS colonization in the index pregnancy was associated with a higher risk of recurrence of GBS colonization in a subsequent pregnancy (three studies: 50.2 compared with 14.1%; pooled fixed effects OR, 6.05; 95% confidence interval [CI], 4.84-7.55). When heavy colonization with GBS was compared with colonization by vaginal culture only, an increased risk of recurrence was shown (four studies: 52.0 compared with 45.1%, pooled fixed effects OR, 1.54; 95% CI, 1.02-2.31). Conclusion Women colonized with GBS are at significantly higher odds for recurrent colonization in a subsequent pregnancy when compared with women who were not colonized in an index pregnancy. If the individual is considered heavily colonized with GBS, there appears to be an association with an increased risk compared with conventional culture. Subgroup analysis of the variables time interval ≤ 12 months between subsequent pregnancies, body mass index ≥ 30 kg/m², race, ethnicity, and primiparous in the subsequent pregnancy showed no effect.