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Meta-Analysis
. 2017 Nov 6;65(suppl_2):S133-S142.
doi: 10.1093/cid/cix661.

Preterm Birth Associated With Group B Streptococcus Maternal Colonization Worldwide: Systematic Review and Meta-analyses

Fiorella Bianchi-Jassir  1 , Anna C Seale  1   2 , Maya Kohli-Lynch  1   3 , Joy E Lawn  1 , Carol J Baker  4 , Linda Bartlett  5 , Clare Cutland  6 , Michael G Gravett  7   8 , Paul T Heath  9 , Margaret Ip  10 , Kirsty Le Doare  9   11 , Shabir A Madhi  12   13 , Samir K Saha  14 , Stephanie Schrag  15 , Ajoke Sobanjo-Ter Meulen  16 , Johan Vekemans  17 , Craig E Rubens  7   18
Affiliations
Meta-Analysis

Preterm Birth Associated With Group B Streptococcus Maternal Colonization Worldwide: Systematic Review and Meta-analyses

Fiorella Bianchi-Jassir et al. Clin Infect Dis. .

Abstract

Background: Preterm birth complications are the leading cause of deaths among children <5 years of age. Studies have suggested that group B Streptococcus (GBS) maternal rectovaginal colonization during pregnancy may be a risk factor for preterm delivery. This article is the fifth of 11 in a series. We aimed to assess the association between GBS maternal colonization and preterm birth in order to inform estimates of the burden of GBS.

Methods: We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus) and sought unpublished data from investigator groups on the association of preterm birth (<37 weeks' gestation) and maternal GBS colonization (GBS isolation from vaginal, cervical, and/or rectal swabs; with separate subanalysis on GBS bacteriuria). We did meta-analyses to derive pooled estimates of the risk and odds ratios (according to study design), with sensitivity analyses to investigate potential biases.

Results: We identified 45 studies for inclusion. We estimated the risk ratio (RR) for preterm birth with maternal GBS colonization to be 1.21 (95% confidence interval [CI], .99-1.48; P = .061) in cohort and cross-sectional studies, and the odds ratio to be 1.85 (95% CI, 1.24-2.77; P = .003) in case-control studies. Preterm birth was associated with GBS bacteriuria in cohort studies (RR, 1.98 [95% CI, 1.45-2.69]; P < .001).

Conclusions: From this review, there is evidence to suggest that preterm birth is associated with maternal GBS colonization, especially where there is evidence of ascending infection (bacteriuria). Several biases reduce the chance of detecting an effect. Equally, however, results, including evidence for the association, may be due to confounding, which is rarely addressed in studies. Assessment of any effect on preterm delivery should be included in future maternal GBS vaccine trials.

Keywords: bacteriuria; colonization; group B Streptococcus; preterm delivery; preterm labor.

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Figures

Figure 1.
Figure 1.
Preterm birth in the disease schema for group B streptococcal disease, as described by Lawn et al [15]. Abbreviations: GBS, group B Streptococcus; NE, neonatal encephalopathy.
Figure 2.
Figure 2.
Search strategy and study selection for analyzing the potential association between maternal group B Streptococcus (GBS) colonization and preterm birth.
Figure 3.
Figure 3.
Countries where published and unpublished data were found for the analyses.
Figure 4.
Figure 4.
Pooled estimates of association between preterm birth and maternal group B Streptococcus (GBS) colonization, split by study design. A, Cohort or cross-sectional studies by time of maternal GBS screening. B, Case-control studies. Abbreviations: CI, confidence interval; OR, odds ratio.
See this image and copyright information in PMC

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