ArticleBMJ open2020
Impact of preconception vaginal microbiota on women's risk of spontaneous preterm birth: protocol for a prospective case-cohort study.
Article in BMJ open, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
13 citing papers in PubMed, 1 synthesis or guideline pooled it, 20 citations in OpenAlex.
- Trichomoniasis and adverse birth outcomes: a systematic review and meta-analysis.BJOG : an international journal of obstetrics and gynaecology · 2021Pooled it
- Article
- Exploration of the mechanism of PCOS induced by microenvironmental changes in follicular fluid based on 16 S rRNA and metabolomics.Journal of ovarian research · 2025Article
- Vaginal host immune-microbiome-metabolite interactions associated with spontaneous preterm birth in a predominantly white cohort.NPJ biofilms and microbiomes · 2025Article
- A prospective cohort study examining the association between the periconceptual vaginal microbiota and first-trimester miscarriage in Kenyan women.Paediatric and perinatal epidemiology · 2024Article
- A prospective preconception cohort study of the association between Mycoplasma genitalium and fecundability in Kenyan women trying to conceive.Human reproduction (Oxford, England) · 2023Article
- Changes in Vaginal Bacteria and Inflammatory Mediators From Periconception Through the Early Postpartum Period in a Cohort of Kenyan Women Without HIV.The Journal of infectious diseases · 2023Article
- Prevalence and correlates of periodontitis among Kenyan women planning to conceive.BMC oral health · 2022Article
- Cultivable vaginal Lactobacillus is not associated with fecundability in Kenyan women attempting to conceive.Fertility and sterility · 2022Article
- Vaginal washing behaviour and fecundability among Kenyan women in a prospective preconception cohort.Paediatric and perinatal epidemiology · 2022Article
- Association between bacterial vaginosis and fecundability in Kenyan women planning pregnancies: a prospective preconception cohort study.Human reproduction (Oxford, England) · 2021Article
- Gut and Reproductive Tract Microbiota Adaptation during Pregnancy: New Insights for Pregnancy-Related Complications and Therapy.Microorganisms · 2021Review
- Comparative Analysis of Lower Genital Tract Microbiome Between PCOS and Healthy Women.Frontiers in physiology · 2020Article
Corrections and comments
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Authors and funding
13 authors at 6 institutions in 2 countries.
Funding
Abstract
introductionBacterial vaginosis (BV) and vaginal microbiota disruption during pregnancy are associated with increased risk of spontaneous preterm birth (SPTB), but clinical trials of BV treatment during pregnancy have shown little or no benefit. An alternative hypothesis is that vaginal bacteria present around conception may lead to SPTB by compromising the protective effects of cervical mucus, colonising the endometrial surface before fetal membrane development, and causing low-level inflammation in the decidua, placenta and fetal membranes. This protocol describes a prospective case-cohort study addressing this hypothesis. METHODS AND ANALYSIS: HIV-seronegative Kenyan women with fertility intent are followed from preconception through pregnancy, delivery and early postpartum. Participants provide monthly vaginal specimens during the preconception period for vaginal microbiota assessment. Estimated date of delivery is determined by last menstrual period and first trimester obstetrical ultrasound. After delivery, a swab is collected from between the fetal membranes. Placenta and umbilical cord samples are collected for histopathology. Broad-range 16S rRNA gene PCR and deep sequencing of preconception vaginal specimens will assess species richness and diversity in women with SPTB versus term delivery. Concentrations of key bacterial species will be compared using quantitative PCR (qPCR). Taxon-directed qPCR will also be used to quantify bacteria from fetal membrane samples and evaluate the association between bacterial concentrations and histopathological evidence of inflammation in the fetal membranes, placenta and umbilical cord. ETHICS AND DISSEMINATION: This study was approved by ethics committees at Kenyatta National Hospital and the University of Washington. Results will be disseminated to clinicians at study sites and partner institutions, presented at conferences and published in peer-reviewed journals. The findings of this study could shift the paradigm for thinking about the mechanisms linking vaginal microbiota and prematurity by focusing attention on the preconception vaginal microbiota as a mediator of SPTB.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.