Vaginal dysbiosis - the association with reproductive outcomes in IVF patients: a systematic review and meta-analysis.
Level 2 - randomized trial
Systematic review and meta-analysis of observational cohort studies
PubMed 38597377 · doi:10.1097/GCO.0000000000000953
What was done
A systematic review and meta-analysis searched PubMed/Medline through December 2023 to evaluate the association of vaginal dysbiosis (VD), including bacterial vaginosis (BV) and aerobic vaginitis (AV), with reproductive outcomes in IVF patients. The review included 25 studies encompassing 6,835 IVF patients. Vaginal dysbiosis was defined as an approximation of community state type IV, including BV and AV diagnosed by molecular or microscopy methods. Evaluated outcomes were live birth rate (LBR), early pregnancy loss (EPL), clinical pregnancy rate (CPR), and biochemical pregnancy rate (BPR).
What was found
The overall prevalence of vaginal dysbiosis was 19% (1,271/6,835; 95% CI 18%–20%), and AV-type dysbiosis prevalence across six studies was 4% (26/628; 95% CI 3%–6%). Vaginal dysbiosis was significantly associated with higher early pregnancy loss (RR = 1.49, 95% CI 1.15–1.94) and lower clinical pregnancy rates (RR = 0.82, 95% CI 0.70–0.95). No statistically significant effect of VD, BV, or AV was found on live birth rate or biochemical pregnancy rate.
Why it matters
This meta-analysis demonstrates that roughly one in five IVF patients has vaginal dysbiosis and that dysbiosis correlates with higher early pregnancy loss and reduced clinical pregnancy. However, the lack of an observed effect on final live birth rates indicates that the overall clinical impact remains unclear.
Limits
The included studies were observational cohorts with heterogeneous diagnostic criteria, combining molecular and microscopic definitions of dysbiosis. The literature search was restricted to a single database (PubMed/Medline). The discordance in results—showing an impact on clinical pregnancy and pregnancy loss but not on live birth or biochemical pregnancy—suggests potential unmeasured confounders, variable outcome reporting, or power limitations for the live birth outcome.
Cited by
- supports Vaginal microbiome community state type IV (CST IV) is associated with worse pregnancy outcomes and lower IVF success.