BJOG. 2021 Jun 17. doi: 10.1111/1471-0528.16816. Online ahead of print.
ABSTRACT
OBJECTIVE: To assess the association between vaginal microbiome (VMB) composition and recurrent early spontaneous preterm birth (sPTB)/preterm prelabour rupture of membranes (PPROM).
DESIGN: Nested case-control study.
SETTING: UK tertiary referral hospital.
SAMPLE: High-risk women with previous sPTB/PPROM <34+0 weeks gestation who had a recurrence (n=22) or delivered at ≥37+0 weeks without PPROM (n=87).
METHODS: Vaginal swabs collected between 15-22 weeks gestation were analysed by 16S rRNA gene sequencing and 16S quantitative PCR.
MAIN OUTCOME MEASURE: Recurrent early sPTB/PPROM.
RESULTS: 28/109 high-risk women had anaerobic vaginal dysbiosis, with the remainder dominated by lactobacilli (L. iners 36/109, L. crispatus 23/109, or other 22/109). VMB type and diversity were not associated with recurrence. Women with a recurrence, compared to those without, had a higher median vaginal bacterial load (8.64 vs. 7.89 log10 cells/μl, adjusted odds ratio (aOR)=1.90, 95% confidence interval (CI)=1.01-3.56, p=0.047) and estimated Lactobacillus concentration (8.59 vs. 7.48 log10 cells/μl, aOR=2.35, CI=1.20-4.61, p=0.013). A higher recurrence risk was associated with higher median bacterial loads for each VMB type after stratification, although statistical significance was reached only for L. iners-domination (aOR=3.44, CI=1.06-11.15, p=0.040). Women with anaerobic dysbiosis or L. iners-domination had a higher median vaginal bacterial load than women with a VMB dominated by L. crispatus or other lactobacilli (8.54, 7.96, 7.63, and 7.53 log10 cells/μl, respectively).
CONCLUSIONS: Vaginal bacterial load is associated with early sPTB/PPROM recurrence. Domination by lactobacilli other than L. iners may protect women from developing high bacterial loads. Future PTB studies should quantify vaginal bacteria and yeasts.
PMID:34139060 | DOI:10.1111/1471-0528.16816
