Reproductive outcome of patients undergoing in vitro fertilisation treatment and diagnosed with bacterial vaginosis or abnormal vaginal microbiota: a systematic <scp>PRISMA</scp> review and meta‐analysis

Haahr, Thor; Zacho, Jeppe; Bräuner, M; Shathmigha, K; Jensen, Jørgen Skov; Humaıdan, Peter

doi:10.1111/1471-0528.15178

Cited by 93 publications

(105 citation statements)

References 39 publications

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“…Earlier studies using non‐objective, symptomatic measures suggested infection as a rare cause of pregnancy loss, but a recent study reported histological chorioamnionitis in 78/101 (77%) of miscarriage samples compared with 0/103 (0%) of controls, with 47% of chorioamnionitis cases culture‐positive . Moreover, a relation between bacterial vaginosis (BV) and increased risk of miscarriage has been described and chlamydial infection is thought to cause miscarriage through impairment of endometrial decidualisation …”

Section: Introductionmentioning

confidence: 99%

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Al‐Memar

Bobdiwala

Fourie

et al. 2019

BJOG

107

110

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Objective To characterise vaginal bacterial composition in early pregnancy and investigate its relationship with first and second trimester miscarriages.Design Nested case-control study.Setting Queen Charlotte's and Chelsea Hospital, Imperial College Healthcare NHS Trust, London.Population 161 pregnancies: 64 resulting in first trimester miscarriage, 14 in second trimester miscarriage and 83 term pregnancies.Methods Prospective profiling and comparison of vaginal bacteria composition using 16S rRNA gene-based metataxonomics from 5 weeks' gestation in pregnancies ending in miscarriage or uncomplicated term deliveries matched for age, gestation and body mass index.Main outcome measures Relative vaginal bacteria abundance, diversity and richness. Pregnancy outcomes defined as first or second trimester miscarriage, or uncomplicated term delivery.Results First trimester miscarriage associated with reduced prevalence of Lactobacillus spp.-dominated vaginal microbiota classified using hierarchical clustering analysis (65.6 versus 87.7%; P = 0.005), higher alpha diversity (mean Inverse Simpson Index 2.5 [95% confidence interval 1.8-3.0] versus 1.5 [1.3-1.7], P = 0.003) and higher richness 25.1 (18.5-31.7) versus 16.7 (13.4-20), P = 0.017), compared with viable pregnancies. This was independent of vaginal bleeding and observable before first trimester miscarriage diagnosis (P = 0.015). Incomplete/complete miscarriage associated with higher proportions of Lactobacillus spp.-depleted communities compared with missed miscarriage. Early pregnancy vaginal bacterial stability was similar between miscarriage and term pregnancies.Conclusions These findings associate the bacterial component of vaginal microbiota with first trimester miscarriage and indicate suboptimal community composition is established in early pregnancy. While further studies are required to elucidate the mechanism, vaginal bacterial composition may represent a modifiable risk factor for first trimester miscarriage.Keywords First trimester miscarriage, second trimester miscarriage, vaginal bacteria, vaginal microbiome.Tweetable abstract Vaginal bacterial composition in first trimester miscarriage is associated with reduced Lactobacillus spp. abundance and is independent of vaginal bleeding.

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Section: Introductionmentioning

confidence: 99%

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Al‐Memar

Bobdiwala

Fourie

et al. 2019

BJOG

107

110

View full text Add to dashboard Cite

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“…BV is characterized by a reduction of vaginal Lactobacillus abundance and an increase in the number of other facultative anaerobic bacteria[3]. A dysbiotic VMB and BV have been reported to be an important risk factor for STI acquisition and adverse reproductive outcomes[4]. Most healthy women have a stable and relatively simple vaginal bacterial community dominated by one single Lactobacillus spp.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the vaginal DNA virome in health and dysbiosis: an opening study in patients with non-female factor infertility

Jakobsen

Haahr

Humaıdan

et al. 2019

Preprint

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18Background. Bacterial vaginosis (BV) is characterised by a reduction in Lactobacillus spp. abundance and 19 increased abundance of facultative anaerobes, like Gardnerella vaginalis. BV aetiology is not fully 20 understood, but bacteriophages could play a pivotal role causing perturbation of the vaginal bacterial 21 community. Here we investigate the vaginal viral community, including bacteriophages, and its association 22 to the bacterial community and BV-status. 23 Methods. Vaginal samples from 48 patients undergoing IVF treatment for non-female factor infertility were 24 subjected to metagenomic sequencing of purified virus-like particles. The vaginal viral community was 25 characterized and correlated with BV-status, bacterial community structure and presence of key vaginal 26 bacterial species. 27 Results. The majority of identified vaginal viruses belonged to the class of double-stranded DNA 28 bacteriophages, with eukaryotic viruses constituting 4% of total reads. Clear links between viral community 29 composition and BV (q = 0.006, R = 0.26) as well as presence of L. crispatus (q = 0.001, R = 0.43), L. iners, 30 Gardnerella vaginalis and Atopobium vaginae were found (q < 0.002, R > 0.15). Interestingly, also the 31 eukaryotic viral community was correlated with BV-status (q = 0.018, R = 0.20). 32 Conclusions. The vaginal virome is clearly linked with bacterial community structure and BV-status. 33 Clinical Trials Registration. NCT02042352. 34 Word count abstract: 200 36 Word count main text: 3467 37

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“…Although there are relatively few studies that have addressed the microbiome of the female reproductive tract with regard to reproductive outcome, two meta‐analyses found BV and abnormal lower genital tract microbiota was significantly more common in patients undergoing fertility treatment compared to the general population, with at least one in five infertility patients having BV, and at least one in three having a disturbed vaginal microbiota . However, these same meta‐analyses found that BV does not impinge on conception rates, although there was an increase rate of pre‐clinical pregnancy loss .…”

Section: Discussionmentioning

confidence: 99%

Investigating the effect of an abnormal cervico‐vaginal and endometrial microbiome on assisted reproductive technologies: A systematic review

Bracewell‐Milnes

Saso

Nikolaou

et al. 2018

American J Rep Immunol

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The female reproductive tract has an active microbiome, and it is suggested that these microbes could influence the outcome of assisted reproductive technologies (ART). This systematic review aimed to assess the vaginal/uterine microbiome, specifically with regard to improving the outcome of ART. English peer-reviewed journals were searched for studies investigating the vaginal/uterine micriobiome and female reproductive tract, using PRISMA guidelines. Twenty-six studies were included, 19 studying the vaginal and seven investigating the uterine microbiome. Studies using culture-based technologies found an abnormal vaginal microbiome AVM was not associated with ART outcome. However, studies using sequence-based technologies found an abnormal vaginal microbiome had a negative effect on ART. An abnormal uterine microbiome impacted ART outcome in all of the studies which used culture-based methods and the most extensive of the two studies using metagenomic sequencing. This review has revealed a lack of translational data relating an abnormal vaginal/uterine microbiome to ART outcomes, with inconsistencies between the results of the different studies. Therefore the nature of the relationship between the vaginal/uterine microbiome and fertility remains unknown. As we better characterize this relationship using modern metagenomic techniques, the potential to manipulate the female reproductive tract microbiome to improve ART could be a reality.

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Reproductive outcome of patients undergoing in vitro fertilisation treatment and diagnosed with bacterial vaginosis or abnormal vaginal microbiota: a systematic PRISMA review and meta‐analysis

Abstract: Abnormal vaginal microbiota is associated with early spontaneous abortion in IVF patients.

Cited by 93 publications

References 39 publications

The association between vaginal bacterial composition and miscarriage: a nested case–control study

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Characterization of the vaginal DNA virome in health and dysbiosis: an opening study in patients with non-female factor infertility

Investigating the effect of an abnormal cervico‐vaginal and endometrial microbiome on assisted reproductive technologies: A systematic review

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