Distinct vaginal microbial signatures in pregnancies complicated by antiphospholipid syndrome: depletion of <i>Lactobacillus johnsonii</i> and enrichment of <i>Bifidobacterium dentium</i>Original paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked whether the vaginal microbiome differs in pregnancies complicated by antiphospholipid syndrome (APS), a systemic autoimmune disease linked to recurrent pregnancy loss and preeclampsia. Researchers profiled the vaginal microbiota using full-length 16S rRNA gene sequencing across the V1-V9 regions on a PacBio long-read platform. They then built a logistic regression risk score from species-level relative abundances and tested it against clinical and pregnancy-outcome data.
Who was studied?
The cohort was 123 pregnant women at a tertiary referral center in Wuhan, China, sampled from March 2024 to March 2025. It included 33 women meeting the revised Sydney criteria for APS and 90 matched healthy pregnant controls. Of the 33 APS pregnancies, 19 were diagnosed before pregnancy and 14 were newly diagnosed during the index pregnancy. All were singleton pregnancies sampled in the third trimester. Vaginal swabs supplied the microbial DNA.
What were the most important findings?
APS pregnancies showed selective compositional restructuring rather than global dysbiosis, with overall diversity and Lactobacillus dominance largely preserved. Hierarchical clustering defined three ecotypes, and 31 of 33 APS samples fell into one ecotype (CT2), while controls spread across the other two. At the genus level, Bifidobacterium was enriched in APS while Lactobacillus dominated controls. One protective species was reduced to 0.019% relative abundance in APS versus 0.895% in controls (p < 0.001). A two-marker logistic model reached an AUC of 0.824 (95% CI 0.746-0.902), with 81.8% sensitivity and 77.5% specificity. Risk scores correlated negatively with red blood cell count (r = -0.240, p = 0.009), gravidity (r = -0.248, p = 0.007), and gestational age at delivery (r = -0.267, p = 0.004).
What are the greatest implications of this study?
The findings suggest APS pregnancies carry a species-specific vaginal microbial signature that tracks with hematological measures and adverse pregnancy histories. This points to vaginal swabs as a possible noninvasive tool for risk stratification. The design is observational and cross-sectional, so it cannot establish whether the microbial shifts cause pregnancy morbidity or reflect it. The cohort was single-center with only 33 APS cases, so external validation is needed before clinical use.