Vaginal microbiome composition in pregnant and non-pregnant women: community structure, population variation, clinical impact, and metagenomics approaches.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing existing literature without systematic review methodology
PubMed 42295167 · doi:10.1128/iai.00542-25
What was done
Narrative review synthesizing published studies on vaginal microbiome composition and dynamics in pregnant and non-pregnant women. The review evaluates evidence from 16S rRNA sequencing, next-generation sequencing, and shotgun metagenomics across gestation and postpartum, focusing on community state types, gestational remodeling, population-specific variation, and clinical outcomes.
What was found
The abstract reports no numerical data. Qualitatively, pregnancy is characterized by decreased microbial diversity and increased dominance of Lactobacillus species (particularly Lactobacillus crispatus), which is associated with stability and favorable outcomes. Conversely, high-diversity anaerobic communities (CST IV) correlate with bacterial vaginosis, preterm birth, miscarriage, gestational diabetes mellitus, and infections. Microbial profiles also differ across populations, with African-descended groups showing higher frequencies of L. iners or diverse anaerobic profiles and European groups more frequently showing L. crispatus dominance.
Why it matters
This review outlines the structural microbiome shifts associated with pregnancy and emphasizes demographic variation that must be accounted for when assessing microbiome-related obstetric risks.
Limits
As a narrative review, it lacks systematic search criteria, quality appraisal, and meta-analytic pooling. The underlying evidence base is largely observational and correlational, meaning causality between specific vaginal microbial profiles and adverse pregnancy outcomes remains unestablished.
Cited by
- supports Vaginal microbiome community state type IV (CST IV) is associated with worse pregnancy outcomes and lower IVF success.