Hormonal contraception is associated with a reduced risk of bacterial vaginosis: a systematic review and meta-analysis

PLoS One. 2013 Sep 4;8(9):e73055. doi: 10.1371/journal.pone.0073055. eCollection 2013.

Abstract

Objective: To examine the association between hormonal contraception (HC) and bacterial vaginosis (BV) by systematic review and meta-analysis.

Methods: Medline, Web of Science and Embase databases were searched to 24/1/13 and duplicate references removed. Inclusion criteria 1) >20 BV cases; 2) accepted BV diagnostic method; 3) measure of HC-use either as combined oestrogen-progesterone HC (combined), progesterone-only contraception (POC) or unspecified HC (u-HC); 4) ≥ 10% of women using HC; 5) analysis of the association between BV and HC-use presented; 6) appropriate control group. Data extracted included: type of HC, BV diagnostic method and outcome (prevalent, incident, recurrent), and geographical and clinic-setting. Meta-analyses were conducted to calculate pooled effect sizes (ES), stratified by HC-type and BV outcome. This systematic review is registered with PROSPERO (CRD42013003699).

Results: Of 1713 unique references identified, 502 full-text articles were assessed for eligibility and 55 studies met inclusion criteria. Hormonal contraceptive use was associated with a significant reduction in the odds of prevalent BV (pooled effect size by random-effects [reES] = 0.68, 95%CI0.63-0.73), and in the relative risk (RR) of incident (reES = 0.82, 95%CI:0.72-0.92), and recurrent (reES = 0.69, 95%CI:0.59-0.91) BV. When stratified by HC-type, combined-HC and POC were both associated with decreased prevalence of BV and risk of incident BV. In the pooled analysis of the effect of HC-use on the composite outcome of prevalent/incident/recurrent BV, HC-use was associated with a reduced risk of any BV (reES = 0.78, 95%CI:0.74-0.82).

Conclusion: HC-use was associated with a significantly reduced risk of BV. This negative association was robust and present regardless of HC-type and evident across all three BV outcome measures. When stratified by HC-type, combined-HC and POC were both individually associated with a reduction in the prevalence and incidence of BV. This meta-analysis provides compelling evidence that HC-use influences a woman's risk of BV, with important implications for clinicians and researchers in the field.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Contraception / methods*
  • Female
  • Hormones / metabolism*
  • Humans
  • Prevalence
  • Risk
  • Vaginosis, Bacterial / epidemiology
  • Vaginosis, Bacterial / prevention & control*

Substances

  • Hormones

Grants and funding

Two grants contributed funding to this study; an NHMRC Project Grant (1020457) & an NHMRC Program grant (568971). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.