Vaginal Microbiota and In Vitro Fertilization Outcomes: Development of a Simple Diagnostic Tool to Predict Patients at Risk of a Poor Reproductive Outcome

An updated study of the relationship between bacterial infections and women's immune system, focusing on bacterial compositions with successful pregnancy

Genital tract infections can cause a variety of harmful health outcomes, including endometritis, bacterial vaginosis, and pelvic inflammatory disease, in addition to infertility. Anaerobic bacteria, such as Gardnerella vaginalis, Megasphaera spp., and Atopobium vaginae, are more commonly identified in cases of bacterial vaginosis than lactobacilli. It is unknown how the microorganisms that cause pelvic inflammatory diseases and endometritis enter the uterus. Both prospective and retrospective research have connected pelvic inflammatory disorders, chronic endometritis, and bacterial vaginosis to infertility. Similar to bacterial vaginosis, endometritis-related infertility is probably caused by a variety of factors, such as inflammation, immune system recognition of sperm antigens, bacterial toxins, and a higher risk of STDs. Preconception care for symptomatic women may include diagnosing and treating pelvic inflammatory disease, chronic endometritis, and bacterial vaginosis before conception to optimize the results of both natural and assisted reproduction.

Pilot Study on Next-Generation Sequencing Analysis of Vaginal Microbiota in Clinically Infertile Patients Treated with Probiotics

Background: In this investigation, we aimed to understand the influence of oral probiotic supplementation on the vaginal microbiota of women preparing for assisted reproductive technology (ART) procedures. Given the importance of a healthy microbiome for reproductive success, this study sought to explore how probiotics might alter the bacterial composition in the vaginal environment. Methods: We recruited a cohort of 30 women, averaging 37 years of age (ranging from 31 to 43 years), who were scheduled to undergo ART. Using 16S ribosomal RNA (rRNA) sequencing, we meticulously analyzed the vaginal microbiota composition before and after the administration of oral probiotic supplements. Results: Our analysis identified 17 distinct microorganisms, including 8 species of Lactobacillus. Following probiotic supplementation, we observed subtle yet notable changes in the vaginal microbiota of some participants. Specifically, there was a decrease in Gardnerella abundance by approximately 20%, and increases in Lactobacillus and Bifidobacterium by 10% and 15%, respectively. Additionally, we noted a significant reduction in the Firmicutes/Bacteroidetes (F/B) ratio in the probiotic group, indicating potential shifts in the overall bacterial composition. Conclusions: These preliminary findings suggest that oral probiotic supplementation can induce significant changes in the vaginal microbiota of middle-aged women undergoing ART, potentially improving their overall bacterial profile. Future studies should consider a larger sample size and a narrower age range to validate these results. Investigating factors related to female hormone production could also provide deeper insights. Understanding the effects of probiotics on the vaginal microbiota in patients with ovarian aging may lead to personalized interventions and better reproductive outcomes.

Microbiome in Female Reproductive Health: Implications for Fertility and Assisted Reproductive Technologies

The microbiome plays a critical role in the process of conception and the outcomes of pregnancy. Disruptions in microbiome homeostasis in women of reproductive age can lead to various pregnancy complications, which significantly impact maternal and fetal health. Recent studies have associated the microbiome in the female reproductive tract (FRT) with assisted reproductive technology (ART) outcomes, and restoring microbiome balance has been shown to improve fertility in infertile couples. This review provides an overview of the role of the microbiome in female reproductive health, including its implications for pregnancy outcomes and ARTs. Additionally, recent advances in the use of microbial biomarkers as indicators of pregnancy disorders are summarized. A comprehensive understanding of the characteristics of the microbiome before and during pregnancy and its impact on reproductive health will greatly promote maternal and fetal health. Such knowledge can also contribute to the development of ARTs and microbiome-based interventions.

Longitudinal analysis of vaginal microbiota during IVF fresh embryo transfer and in early pregnancy

IMPORTANCE

Infertility is a global public health issue which leads many couples to seek fertility treatments, of which in vitro fertilization (IVF) is considered to be the most effective. Still, only about one-third of the women achieve live birth after the first IVF embryo transfer (IVF-ET). Factors affecting embryo implantation are poorly known, but the female reproductive tract microbiota may play a key role. Our study confirms the beneficial role of vaginal lactobacilli, especially Lactobacillus crispatus, in the probability of achieving clinical pregnancy and live birth following IVF-ET. Our findings regarding the intra-individual shift of vaginal microbiota between non-pregnancy and pregnancy states are novel and provide new information about the dynamics of microbiota in the early steps of human reproduction. These findings may help clinicians in their attempts to optimize the conditions for ET by microbiota screening or modulation and timing the ET when the microbiota is the most favorable.

Bacterial Vaginosis: Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry No. 015/028, June 2023)

Aim This official guideline was coordinated and published by the DGGG, OEGGG and SGGG with the involvement of additional professional societies. The aim of the guideline is to evaluate the relevant literature and use it to provide a consensus-based overview of the diagnosis and management of bacterial vaginosis. Methods This S2k-guideline was developed by representative members from different medical professional societies on behalf of the guidelines commission of the above-listed societies using a structured consensus process. Recommendations This guideline provides recommendations on the diagnosis, management, counselling, prophylaxis, and other aspects related to bacterial vaginosis.

Systematic review and meta-analysis of maternal and fetal outcomes among pregnant women with bacterial vaginosis

BACKGROUND

Women of childbearing age are commonly affected by bacterial vaginosis (BV). Maternal-fetal outcomes associated with BV during pregnancy can be fatal for both the mother and the newborn.

AIM

To identify maternal and fetal outcomes in pregnant women with BV encountered globally, highlight their prevalence, and identify maternal-fetal outcomes associated with BV.

METHODS

The databases Embase, PubMed, Web of Science and Global Index Medicus were searched from inception until December 2022. No restrictions on time or geographical location were imposed when searching for published articles that examined maternal-fetal outcomes in pregnant women with BV. A random effects model was used to perform the meta-analysis. Sources of heterogeneity were investigated using subgroup analysis, and publication bias was assessed using funnel plots and Egger tests.

FINDINGS

In total, 26 of the 8983 articles retrieved from the databases met the inclusion criteria and were included in this study. Twenty-two maternal outcomes and 22 fetal outcomes were recorded among pregnant women with BV worldwide. This study determined the prevalence of maternal-fetal outcomes reported in three or more studies. Among fetal outcomes, preterm birth (PTB) had the highest prevalence [17.9%, 95% confidence interval (CI) 13-23.3%], followed by mechanical ventilation (15.2%, 95% CI 0-45.9%), low birth weight (LBW) (14.2%, 95% CI 9.1-20.1%) and neonatal intensive care unit admission (11.2%, 95% CI 0-53.5%). BV was associated with PTB [odds ratio (OR) 1.76, 95% CI 1.32-2.35], LBW (OR 1.73, 95% CI 1.41-2.12) and birth asphyxia (OR 2.90, 95% CI 1.13-7.46). Among maternal outcomes, premature rupture of membranes (PROM) had the highest prevalence (13.2%, 95% CI 6.1-22.3%). BV was associated with the following maternal outcomes: intrauterine infection (OR 2.26, 95% CI 1.44-3.56), miscarriage (OR 2.34, 95% CI 1.18-4.64) and PROM (OR 2.59, 95% CI 1.39-4.82). Maternal and fetal outcomes were most prevalent in women whose BV was diagnosed using the Amsel criteria (37.2%, 95% CI 23-52.6%) and in the third trimester (29.6%, 95% CI 21.2-38.8%). Although reported in fewer than three studies, some maternal-fetal outcomes are highly prevalent, such as respiratory distress (76.67%, 95% CI 57.72-90.07%), dyspareunia (68.33%, 95% CI 55.04-79.74%) and malodorous discharge (85.00%, 95% CI 73.43-92.90%).

CONCLUSION

BV has been associated with several adverse maternal-fetal outcomes around the world. While BV is a common vaginal infection, the types of maternal-fetal outcomes from pregnant women with BV vary by country.

Epidemiologic Evidence on the Role of Lactobacillus iners in Sexually Transmitted Infections and Bacterial Vaginosis: A Series of Systematic Reviews and Meta-Analyses

ABSTRACT

Although Lactobacillus crispatus -dominated vaginal microbiotas are thought to protect against bacterial vaginosis (BV) and sexually transmitted infections, the role of Lactobacillus iners -dominated microbiotas is less clear. To better understand the impact of L. iners on common cervicovaginal infections, we conducted systematic reviews of the associations between L. iners compared with L. crispatus and 8 outcomes: Chlamydia trachomatis (Ct), BV, human papillomavirus, cervical dysplasia, human immunodeficiency virus, genital herpes, Trichomonas vaginalis , and Neisseria gonorrhoeae . On April 30, 2021, we searched PubMed, Embase, Cochrane Library, and Web of Science for epidemiologic studies of reproductive-age, nonpregnant, cisgender women that used marker gene sequencing to characterize vaginal microbiota composition and presented an effect estimate for the association between L. iners , compared with L. crispatus , and outcomes of interest. For outcomes with ≥3 eligible results presenting the same form of effect estimate, we conducted random-effects meta-analysis. The review protocol was registered prospectively (PROSPERO CRD42020214775). Six Ct studies were included in meta-analysis, which showed L. iners -dominated microbiotas were associated with 3.4-fold higher odds of Ct compared with L. crispatus -dominated microbiotas (95% confidence interval, 2.1-5.4). Three BV studies were included in meta-analysis, which indicated L. iners -dominated microbiotas were associated with 2.1-fold higher prevalence of BV compared with L. crispatus -dominated microbiotas (95% confidence interval, 0.9-4.9). Evidence was too sparse to perform meta-analysis for the remaining outcomes. L. iners -dominated vaginal microbiotas may be suboptimal compared with L. crispatus -dominated microbiotas for BV and Ct. These reviews highlight evidence gaps regarding the remaining outcomes and opportunities to improve epidemiologic rigor in vaginal microbiome science.

Correlations of joint detection of 22 vaginal microbes with routine examination results of vaginal secretions and assisted reproductive outcomes

The correlations of joint detection of 22 vaginal microbes with routine examination results of vaginal secretions and assisted reproductive outcomes were investigated. There were 37 samples with abnormal vaginal microecology in 107 vaginal secretion samples. The top 5 detection rates of microorganisms were Ureaplasma urealyticum (73.83%), Prevotella sp. (70.09%), Gardnerella vaginalis (53.27%), L. crispatus (52.34%) and L. inerts (51.40%). When the levels of Bacillus and hydrogen peroxide in vaginal secretions decreased or pH increased, the abnormal rates of vaginal microecology increased significantly (P < 0.01). The clinical pregnancy rate (53.66%, 22/41) in the women with normal vaginal microecology was higher than that (37.5%, 9/24) with abnormal vaginal microecology. In conclusions, the joint detection of 22 vaginal microbes can quickly and effectively determine whether the vaginal microecology is normal or not. The evaluation of vaginal microecology may be valuable in predicting the assisted reproductive outcomes of infertile women.

The endometrial microbiota of women with or without a live birth within 12 months after a first failed IVF/ICSI cycle

The endometrial microbiota composition may be associated with implantation success. However, a 'core' composition has not yet been defined. This exploratory study analysed the endometrial microbiota by 16S rRNA sequencing (V1-V2 region) of 141 infertile women whose first IVF/ICSI cycle failed and compared the microbiota profiles of women with and without a live birth within 12 months of follow-up, and by infertility cause and type. Lactobacillus was the most abundant genus in the majority of samples. Women with a live birth compared to those without had significantly higher Lactobacillus crispatus relative abundance (RA) (p = 0.029), and a smaller proportion of them had ≤ 10% L. crispatus RA (42.1% and 70.4%, respectively; p = 0.015). A smaller proportion of women in the male factor infertility group had ≤ 10% L. crispatus RA compared to women in the unexplained and other infertility causes groups combined (p = 0.030). Women with primary infertility compared to secondary infertility had significantly higher L. crispatus RA (p = 0.004); lower proportions of them had ≤ 10% L. crispatus RA (p = 0.009) and > 10% Gardnerella vaginalis RA (p = 0.019). In conclusion, IVF/ICSI success may be associated with L. crispatus RA and secondary infertility with endometrial dysbiosis, more often than primary infertility. These hypotheses should be tested in rigorous well-powered longitudinal studies.

Genital Microbiota and Outcome of Assisted Reproductive Treatment-A Systematic Review

The balance between different bacterial species is essential for optimal vaginal health. Microbiome includes the host genome along with microorganism genomes and incorporates the biotic and abiotic factors, reflecting the habitat as a whole. A significant difference exists in the composition and number of the human microbiota in healthy individuals. About one-tenth of the total body microbiota exists in the urogenital tract and these can be identified by microscopy and culture-based methods, quantitative PCR, next generation and whole genome sequencing. The trend of delaying the planning of pregnancy to a later age nowadays has resulted in magnifying the use of assisted reproductive treatment (ART). Hence, genital microbiota and its impact on fertility has generated immense interest in recent years. In this systematic review, we searched the available evidence on the microbiota of the genital tract in women undergoing ART and studied the outcomes of IVF in different microbial compositions. Despite the inconsistency of the studies, it is evident that vaginal, cervical and endometrial microbiota might play a role in predicting ART outcomes. However, there is no clear evidence yet on whether the diversity, richness, quantity, or composition of species in the maternal genital tract significantly affects the outcomes in ARTs.

Cultivable vaginal Lactobacillus is not associated with fecundability in Kenyan women attempting to conceive

OBJECTIVE

To examine the association between cultivable vaginal Lactobacillus and fecundability in Kenyan women attempting nonmedically assisted conception.

DESIGN

Prospective preconception cohort.

SETTING

Nairobi and Mombasa, Kenya.

PATIENT(S)

Women trying to conceive who reported ≤3 months of pre-enrollment conception attempt time.

INTERVENTION(S)

Cultivable Lactobacillus (primary), Lactobacillus morphotypes on Gram stain (secondary).

MAIN OUTCOME MEASURE(S)

Participants reported the first day of their last menstrual period and recent sexual behavior, underwent pregnancy testing, and provided vaginal specimen samples for Lactobacillus culture and Gram stain at ≤6 monthly preconception visits. The outcome was fecundability-the per-menstrual cycle probability of pregnancy. Associations between cultivable Lactobacillus and Lactobacillus morphotypes on Gram stain at the visit before each pregnancy test and fecundability were estimated using proportional probabilities models to generate fecundability ratios (FRs).

RESULT(S)

A total of 458 women contributed 1,376 menstrual cycles. At enrollment, 65.3% (n = 299) of participants had cultivable Lactobacillus, 47.4% (n = 217) had cultivable hydrogen peroxide producing Lactobacillus, and 64.6% (n = 296) had Lactobacillus detected on Gram stain. In unadjusted analysis, there was no association between cultivable Lactobacillus at the prior visit and fecundability (FR, 0.92; 95% CI, 0.73-1.16); results were similar after adjustment for age, frequency of condomless sex, and study site (adjusted FR, 0.92; 95% CI, 0.72-1.18). Lactobacillus on Gram stain at the visit prior was associated with modestly higher fecundability (adjusted FR, 1.18; 95% CI, 0.92-1.51).

CONCLUSION(S)

Cultivable Lactobacillus was not associated with fecundability, although Lactobacillus morphotypes detected on Gram stain were somewhat associated with increased fecundability. The relationship between vaginal Lactobacillus and fecundity may be species-specific.

Identifying Predictive Bacterial Markers from Cervical Swab Microbiota on Pregnancy Outcome in Woman Undergoing Assisted Reproductive Technologies

Background and aims: Failure of the embryo to implant causes about three-fourths of lost pregnancies. Female genital tract microbiota has been associated to Assisted Reproductive Technologies (ART) outcomes. The objective of this study was to analyze the microbiota of human cervical swab and to correlate these findings with the ART outcomes. Materials and Methods: In this study, 88 cervical swabs were collected from women undergoing ART cycles, with various causes of infertility, at the beginning of the ART protocols. After microbial DNA extraction, V3–V4 variable regions of the 16S rRNA gene were amplified and sequenced on the Illumina MiSeq platform. PEnalized LOgistic Regression Analysis (PELORA) was performed to identify clusters of bacterial populations with differential abundances between patients with unfavorable and favorable pregnancy outcome groups, respectively. Results: We identified a core of microorganisms at lower taxonomic levels that were predictive of women’s pregnancy outcomes. Statistically significant differences were identified at species levels with Lactobacillus salivarius, Lactobacillus rhamnosus among others. Moreover the abundance of Lactobacillus crispatus and iners, respectively increased and decreased in favorable group as compared to unfavorable group, resulted within the core of microorganisms associated to positive ART outcome. Although the predominance of lactobacilli is generally considered to be advantageous for ART outcome, we found that also the presence of Bifidobacterium (together with the other lactobacilli) was more abundant in the favorable group. Discussion: Cervix is colonized by microorganisms which can play a role in ART outcomes as seen by an overall decrease in embryo attachment rates and pregnancy rates in both fertile and infertile women. If confirmed in a larger cohort, the abundance of these bacteria can be useful not only as a marker of unfavorable pregnancy outcome but also they may open the way to new interventional strategies based on genital tract microbiota manipulation in order to increase the pregnancy rates in woman undergoing assisted reproductive technologies.

Endometrial Microbiome and Women’s Reproductive Health – Review of the Problem Endometrial Microbiome and Reproductive Health

Currently, unlike in the past, the endometrial cavity is not considered to be sterile. The endometrium is supposed to be dominated by Lactobacilli, but also their deficiency can be found in the reproductive tract of asymptomatic healthy women. Sometimes the endometrial microbiome is dominated by various pathological microorganisms, and this can lead to various conditions as chronic endometritis, chorioamnionitis and preterm birth. Their presence causes uterine inflammation and infection, release of pro-inflammatory molecules, uterine contractions, disruption of cervical barrier, premature rupture of membranes. Uterine dysbiosis is associated with recurrent implantation failure and recurrent miscarriages. As the microbiome is important for maintaining immunological homeostasis at the level of gastrointestinal tract Lactobacilli may play a similar function at the level of uterus. The lactobacillus-dominated uterine microbiome is of great importance for maintaining a hostile uterine microenvironment, embryo implantation, early pregnancy development and normal pregnancy outcome.

The role of gut and genital microbiota and the estrobolome in endometriosis, infertility and chronic pelvic pain

BACKGROUND

Endometriosis is a chronic, burdensome condition that is historically understudied. Consequently, there is a lack of understanding of the etiology of the disease and its associated symptoms, including infertility and chronic pelvic pain (CPP). Endometriosis development is influenced by estrogen metabolism and inflammation, which are modulated by several factors including the microbiome and the estrobolome (the collection of genes encoding estrogen-metabolizing enzymes in the gut microbiome). Therefore, there is increasing interest in understanding the role of microbiota in endometriosis etiology.

OBJECTIVE AND RATIONALE

To date, there is no cure for endometriosis and treatment options often are ineffective. This manuscript will review the potential relationship between the microbiome and endometriosis, infertility and CPP and highlight the available data on the microbiome in relation to endometriosis and its related symptoms. The overarching goal of this manuscript is to inform future microbiome research that will lead to a deeper understanding of the etiology of the disease and possible diagnostic modalities and treatments. The potential impact of the microbiome on estrogen regulation modulated by the estrobolome, as well as inflammation and other endometriosis-promoting mechanisms within the genital tract, will be reviewed. The methodological limitations of microbiome-related studies will be critically assessed to provide improved guidelines for future microbiome and clinical studies.

SEARCH METHODS

PubMed databases were searched using the following keywords: endometriosis AND microbiome, infertility AND microbiome, pelvic pain AND microbiome, IVF (in-vitro fertilization) AND microbiome, endometriosis AND infertility. Clinical and preclinical animal trials that were eligible for review, and related to microbiome and endometriosis, infertility or CPP were included. All available manuscripts were published in 2002-2021.

OUTCOMES

In total, 28 clinical and 6 animal studies were included in the review. In both human and animal studies, bacteria were enriched in endometriosis groups, although there was no clear consensus on specific microbiota compositions that were associated with endometriosis, and no studies included infertility or CPP with endometriosis. However, bacterial vaginosis-associated bacteria and Lactobacillus depletion in the cervicovaginal microbiome were associated with endometriosis and infertility in the majority (23/28) of studies. Interpretation of endometrial studies is limited owing to a variety of methodological factors, discussed in this review. In addition, metadata outlining antibiotic usage, age, race/ethnicity, menopausal status and timing of sample collection in relation to diagnosis of endometriosis was not consistently reported. Animal studies (6/6) support a bidirectional relationship between the gut microbiota and endometriosis onset and progression.

WIDER IMPLICATIONS

There is evidence that a dysbiotic gut or genital microbiota is associated with multiple gynecologic conditions, with mounting data supporting an association between the microbiome and endometriosis and infertility. These microbiomes likely play a role in the gut-brain axis, which further supports a putative association with the spectrum of symptoms associated with endometriosis, including infertility and CPP. Collectively, this review highlights the demand for more rigorous and transparent methodology and controls, consistency across the field, and inclusion of key demographic and clinical characteristics of disease and comparison participants. Rigorous study designs will allow for a better understanding of the potential role of the microbiome in endometriosis etiology and the relationship to other disorders of the female reproductive tract.

Microbiome Compositions From Infertile Couples Seeking In Vitro Fertilization, Using 16S rRNA Gene Sequencing Methods: Any Correlation to Clinical Outcomes?

Background

Bacterial infections are usually suspected in infertile couples seeking IVF with no clear understanding of the microbial compositions present in the seminal fluids and vaginal niche of the patients. We used next-generation sequencing technology to correlate microbiota compositions with IVF clinical outcomes.

Methods

Thirty-six couples were recruited to provide seminal fluids and vaginal swabs. Bacterial DNA was extracted, and V4 region of the 16S rRNA was amplified and sequenced in a pair-end configuration on the Illumina MiSeq platform rendering 2 × 150 bp sequences. Microbial taxonomy to species level was generated using the Greengenes database. Linear discriminant analysis (LDA) effect size (LEfSe) was used to identify biologically and statistically significant differences in relative abundance.

Results

Seminal fluid microbiota compositions had lower bacterial concentrations compared with the vagina, but species diversity was significantly higher in seminal fluid samples. Azoospermic subjects had more relative abundance of Mycoplasma and Ureaplasma. In Normospermic semen, Lactobacillus (43.86%) was the most abundant, followed by Gardnerella (25.45%), while the corresponding vaginal samples, Lactobacillus (61.74%) was the most abundant, followed by Prevotella (6.07%) and Gardnerella (5.86%).

Conclusions

Semen samples with positive IVF were significantly colonized by Lactobacillus jensenii (P=0.002), Faecalibacterium (P=0.042) and significantly less colonized by Proteobacteria, Prevotella, Bacteroides, and lower Firmicutes/Bacteroidetes ratio compared with semen samples with negative IVF. Vaginal samples with positive IVF clinical outcome were significantly colonized by Lactobacillus gasseri, less colonized by Bacteroides and Lactobacillus iners. This study has opened a window of possibility for Lactobacillus replenishments in men and women before IVF treatment.

The Microbial Composition of Lower Genital Tract May Affect the Outcome of in vitro Fertilization-Embryo Transfer

Objective: This work was conducted in order to study the effect of the lower genital tract (vaginal and cervical canal) microbiota on pregnancy outcomes of reproductive-aged women receiving embryo transfer.

Study design: A total of 150 reproductive-aged patients who received the first fresh in vitro fertilization-embryo transfer (IVF-ET) were included in the study. Samples from the vagina and cervical site of each patient were collected separately using sterile swabs before ET. Genomic DNA was pyrosequenced for the V3–V4 regions of the 16S ribosomal RNA gene. Further bioinformatics analysis was performed using QIIME and R package. Pregnancy outcomes were followed and analyzed to compare differences in microbial composition.

Results: The cervical microbiota had a higher Shannon index than the vaginal microbiota, and the microbial composition was different between the two sites. However, the Sorenson index between the two sites within the same individual was 0.370 (0.309–0.400). A total of 89 patients achieved clinical pregnancy after ET, while 61 failed. The Shannon indices and the microbial community of both vaginal and cervical microbiota between pregnant and non-pregnant groups were not significantly different. The relative abundance of Lactobacillus in the vagina and cervical canal did not differ between the two groups. Linear discriminant analysis, random forest analysis, and receiver-operating characteristic curve analysis showed that Bifidobacterium, Prevotella, and Lactobacillus iners in the vagina, as well as Solanum torvum, Fusobacterium, and Streptococcus in the cervix, may be negatively associated with clinical pregnancy after IVF.

Conclusion: The cervical microbiota was more diverse than the vaginal microbiota, but because of anatomical continuity, there was a correlation between the two sites. The microbial composition of the vagina and cervical canal may influence the outcome of IVF-ET, but more samples are needed to verify this conclusion.

Vaginal dysbiosis in pregnancy associates with risk of emergency caesarean section: a prospective cohort study

OBJECTIVES

To investigate changes in vaginal microbiota during pregnancy, and the association between vaginal dysbiosis and reproductive outcomes.

METHODS

A total of 730 (week 24) and 666 (week 36) vaginal samples from 738 unselected pregnant women were studied by microscopy (Nugent score) and characterized by 16S rRNA gene sequencing. A novel continuous vaginal dysbiosis score was developed based on these methods using a supervised partial least squares model.

RESULTS

Among women with bacterial vaginosis in week 24 (n = 53), 47% (n = 25) also had bacterial vaginosis in week 36. In contrast, among women without bacterial vaginosis in week 24, only 3% (n = 18) developed bacterial vaginosis in week 36. Vaginal samples dominated by Lactobacillus crispatus (OR 0.35, 95% CI 0.20-0.60) and Lactobacillus iners (OR 0.40, 95% CI 0.23-0.68) in week 24 were significantly more stable by week 36 when compared with other vaginal community state types. Vaginal dysbiosis score at week 24 was associated with a significant increased risk of emergency, but not elective, caesarean section (OR 1.37, 955 CI 1.15-1.64, p < 0.001), suggesting a 37% increased risk per standard deviation increase in vaginal dysbiosis score.

CONCLUSIONS

Changes in vaginal microbiota from week 24 to week 36 of pregnancy correlated with bacterial vaginosis status and vaginal community state type. A novel vaginal dysbiosis score was associated with a significantly increased risk of emergency, but not elective, caesarean section. This was not found for bacterial vaginosis or any vaginal community state type and could point to the importance of investigating vaginal dysbiosis as a nuanced continuum instead of crude clusters.

Gut and vaginal microbiomes on steroids: implications for women's health

This review discusses the interactions of steroids with the gut and vaginal microbiomes within each life phase of adult women and the implications for women's health. Each phase of a woman's life is characterized by distinct hormonal states which drive overall physiology of both host and commensal microbes. These host-microbiome interactions underlie disease pathology in disorders that affect women across their lifetime, including bacterial vaginosis, gestational diabetes, polycystic ovary syndrome (PCOS), anxiety, depression, and obesity. Although many associations between host health and microbiome composition are well defined, the mechanistic role of the microbiome in women's health outcomes is largely unknown. This review addresses potential mechanisms by which the microbiota influences women's health and highlights gaps in current knowledge.

Diagnosis of bacterial vaginosis: Clinical or microscopic? A cross-sectional study

OBJECTIVE

To compare the performance of the Amsel criteria, culture of Gardnerella spp., and wet mount microscopy (WMM) in the diagnosis of bacterial vaginosis.

METHODS

A cross-sectional cohort study was conducted, consisting of evaluating 749 consecutive women, regardless of symptoms. The Amsel criteria were evaluated, WMM microscopy and Gram staining were performed, and a swab was collected for culture. The gold standard for diagnosis was the Nugent score.

RESULTS

The sensitivity and specificity for the different approaches were: Amsel criteria 41.3% (95% confidence interval [CI] 33.76-49.18) and 97.8% (95% CI 96.21-98.81); cultures 59.9% (95% CI 51.47-67.85) and 99.0% (95% CI 97.76-99.69); WMM 82.6% (95% CI 76.02-88.05) and 92.4% (95% CI 89.98-94.45), respectively. WMM performed equally well in symptomatic and asymptomatic women. Amsel criteria in scenarios where there is no use of a microscope had very poor sensitivity (22.8% [CI 16.63-29.87%]).

CONCLUSION

The Amsel criteria have a poor performance for the diagnosis of bacterial vaginosis. WMM performs well but is not routinely used and should be the first approach for the diagnosis of vaginitis.

Antibacterial and Antifungal Activity of the Human Endometrial Fluid during the Natural Cycle

Purpose

Some microbiota patterns have been associated with favorable IVF prognosis and others with pathological conditions. The endometrial fluid aspirate (EFA) contains antibacterial proteins that are enriched in implantative IVF cycles, but the antimicrobial effect of EFA has not been addressed. We aimed to evaluate the antimicrobial activity of the human endometrial fluid during the natural cycle.

Methods

EFA was obtained through an embryo transfer catheter in 38 women, aged 18-40 years, with regular cycles attending to a fertility clinic. The antimicrobial activity of EFAs was tested against two strains of Staphylococcus aureus; one strain each of Streptococcus agalactiae, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae; and three yeasts (Candida albicans, Candida glabrata, and Candida krusei).

Results

All samples exhibited antibacterial activity against S. aureus. In addition, 32.4% of EFAs were active against one of the other microorganisms assayed, 16.2% against two, and 5.4% against four of them. In contrast, none exhibited antibacterial activity against E. coli or K. pneumoniae. The antimicrobial activity differs considerably between EFA samples, and we failed to observe a cycle-related pattern.

Conclusions

EFA presented two antimicrobial activity patterns: (a) one common to all the samples, exhibiting activity against S. aureus and lack of activity against E. coli and K. pneumoniae, and (b) an individualized pattern, showing activity against some of the other microorganisms tested. The intensity of antibacterial activity differs between EFA samples. Our data suggest that the uterine microbiota is controlled by means of endometrial fluid components.

The vaginal microbiota composition of women undergoing assisted reproduction: a prospective cohort study

OBJECTIVE

To evaluate the impact of vaginal microbiota on pregnancy outcomes in women undergoing assisted reproduction.

DESIGN

A prospective cohort study.

SETTING

A university-based assisted reproductive technology (ART) centre.

POPULATION

223 women undergoing ART treatment.

METHODS

Prior to embryo transfer, vaginal samples were collected from the posterior fornix. Vaginal microbiota identification was carried out using next-generation sequencing and categorised according to the V3-V4 hypervariable region in the 16S rRNA gene region.

MAIN OUTCOME MEASURES

ART clinical outcomes (implantation, clinical pregnancy rates and live birth rates).

RESULTS

The live birth rate in women with community state type (CST)-I (39%) was higher than that in women with CST-III (21.5%) but the difference was not statistically significant (P = 0.052). The relative abundance of Lactobacillus was lower in women who failed to become pregnant (NP group) (67.71%) than in women who became pregnant (PR group) (79.72%). However, this difference was not statistically significant (P = 0.06). In the NP group, the relative abundance of Streptococcus (7.81%) and Gardnerella (9.40%) was higher than that in the PR group (relative abundance of Streptococcus and Gardnerella was 2.28% and 5.56%, respectively). The abundance of Streptococcus was found to be statistically significantly different between the two study groups (P = 0.014). Linear discriminant analysis (LDA) further validated that Streptococcus had the highest contribution (LDA score >4.0) to the difference between these two groups.

CONCLUSIONS

Streptococcus has the highest contribution to the distinction between the PR and NP groups.

TWEETABLE ABSTRACT

A relatively high abundance of Streptococcus in the vaginal microbiota may be associated with a lower ART success rate.

Association between bacterial vaginosis and fecundability in Kenyan women planning pregnancies: a prospective preconception cohort study

STUDY QUESTION

Is bacterial vaginosis (BV) associated with fecundability?

SUMMARY ANSWER

Women with BV may be at increased risk for sub-fecundity.

WHAT IS KNOWN ALREADY

While BV has been associated with poor IVF outcomes, the association between vaginal microbiota disruption and non-medically assisted conception has not been thoroughly explored.

STUDY DESIGN, SIZE, DURATION

Kenyan women with fertility intent were enrolled in prospective cohort that included monthly preconception visits with vaginal fluid specimen collection and pregnancy testing. Four hundred fifty-eight women attempting pregnancy for ≤3 menstrual cycles at enrollment were eligible for this fecundability analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At monthly preconception visits, participants reported the first day of last menstrual period and sexual behavior, underwent pregnancy testing and provided vaginal specimens. Discrete time proportional probabilities models were used to estimate fecundability ratios (FRs) and 95% CI in menstrual cycles with and without BV (Nugent score ≥ 7) at the visit prior to each pregnancy test. We also assessed the association between persistent BV (BV at two consecutive visits) and fecundability.

MAIN RESULTS AND THE ROLE OF CHANCE

Participants contributed 1376 menstrual cycles; 18.5% (n = 255) resulted in pregnancy. After adjusting for age, frequency of condomless sex and study site, BV at the visit prior to pregnancy testing was associated with a 17% lower fecundability (adjusted FR (aFR) 0.83, 95% CI 0.6-1.1). Persistent BV was associated with a 43% reduction in fecundability compared to cycles characterized by optimal vaginal health (aFR 0.57, 95% CI 0.4-0.8).

LIMITATIONS, REASONS FOR CAUTION

Detection of vaginal microbiota disruption using Gram stain and a point-of-care test for elevated sialidase identified a non-optimal vaginal environment, but these non-specific methods may miss important relationships that could be identified by characterizing individual vaginal bacteria and bacterial communities using molecular methods. In addition, results may be subject to residual confounding by condomless sex as this was reported for the prior month rather than for the fertile window during each cycle.

WIDER IMPLICATIONS OF THE FINDINGS

Given the high global prevalence of BV and infertility, an association between BV and reduced fecundability could have important implications for a large number of women who wish to conceive. Multi-omics approaches to studying the vaginal microbiota may provide key insights into this association and identify potential targets for intervention.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a National Institutes of Health grant (NICHD R01 HD087346-R.S.M.). R.S.M. received additional support for mentoring (NICHD K24 HD88229). E.M.L. was supported by pre- and post-doctoral fellowships (NIAID T32 AI07140, NICHD F32 HD100202). Data collection and management were made possible using REDCap electronic data capture tools hosted at the University of Washington's Institute of Translational Health Science supported by grants from NCATS/NIH (UL1 TR002319). The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. R.S.M. receives research funding, paid to the University of Washington, from Hologic Corporation, and has received honoraria for consulting from Lupin Pharmaceuticals. L.E.M. receives research funding, paid to the University of Washington, from Hologic Corporation, and has received honoraria for service on scientific advisory boards from Hologic and Nabriva Therapeutics.

TRIAL REGISTRATION NUMBER

N/A.

The Association between Vaginal Dysbiosis and Reproductive Outcomes in Sub-Fertile Women Undergoing IVF-Treatment: A Systematic PRISMA Review and Meta-Analysis

Recent advances in molecular microbiology have enabled refined studies of the genital tract microbiota. This constitutes the basis of the present updated systematic review and meta-analysis which investigate vaginal dysbiosis (VD) as defined by either microscopy (e.g., Nugent score for bacterial vaginosis) or molecular methods (qPCR and Next Generation Sequencing) to evaluate the impact of VD on the reproductive outcomes in women undergoing IVF-treatment. A total of 17 studies were included, comprising 3543 patients and with a VD prevalence of 18% (95%CI 17–19). Across all methods, VD is a significant risk factor for early pregnancy loss in IVF (Relative risk (RR) = 1.71 95%CI 1.29–2.27). Moreover, a predefined sub-analysis of studies using molecular methods for VD diagnosis showed a significant reduction in the clinical pregnancy rate when compared to normal vaginal microbiota patients (RR = 0.55 95%CI 0.32–0.93). However, regardless of diagnostic methodology, VD did not significantly influence live birth rate (LBR). In conclusion, molecular tools have provided a more detailed insight into the vaginal microbiota, which may be the reason for the increased adverse effect estimates in IVF patients with molecularly defined VD. However, the quality of evidence was very low across all outcomes according to GRADE and thus, more studies are warranted to understand the impact of VD in IVF.

Bacterial vaginosis and its association with infertility, endometritis, and pelvic inflammatory disease

Bacterial vaginosis, pelvic inflammatory disease, and endometritis are infections of the genital tract that can lead to many adverse health outcomes, including infertility. Bacterial vaginosis is characterized by a lower prevalence of lactobacilli and a higher prevalence of anaerobic bacteria, including Gardnerella vaginalis, Megasphaera spp., and Atopobium vaginae. Endometritis and pelvic inflammatory disease are caused by the ascension of pathogenic bacteria to the uterus, although the mechanisms by which they do so are unclear. Bacterial vaginosis, chronic endometritis, and pelvic inflammatory disease have been linked to infertility in retrospective and prospective trials. Similarly, the causes of bacterial vaginosis and endometritis-related infertility are likely multifactorial and stem from inflammation, immune targeting of sperm antigens, the presence of bacterial toxins, and increased risk of sexually transmitted infections. Diagnosis and treatment of bacterial vaginosis, chronic endometritis, and pelvic inflammatory disease before attempting conception may be important components of preconceptional care for symptomatic women to improve outcomes of natural and assisted reproduction.

Vaginal Microbiome Is Associated With Vulvodynia, Vulvar Pain Syndrome: A Case-Control Study

INTRODUCTION

Vulvodynia, vulvar pain syndrome, is defined as vulvar pain of at least a 3-month duration without a clear identifiable cause, which may have associated factor and the etiology and treatment of this challenging disease is still unclear. Dyspareunia is a relevant symptom of patients with vulvodynia. Vaginal microbiome has known an important role in local immune-inflammatory responses and it may be important pathogenic mechanism in vulvodynia.

AIM

The objective of this study was to investigate the association of vaginal microbiome and vulvodynia.

METHODS

We analyzed the microbial compositions of the vestibule and vagina among women with clinically diagnosed vulvodynia (n = 22) and age-matched healthy controls (n = 22) without vulvodynia. The compositions of bacterial microbiomes were compared by pyrosequencing of the 16S rRNA.

MAIN OUTCOME MEASURE

Vaginal microbiome alpha and beta diversity were assessed using the Shannon diversity index and Heat map. Linear discriminant analysis effect size was used to find out marker for vulvodynia.

RESULTS

There were no significant differences in the age, duration of marriage, history of gynecologic surgery, parity, and menopause status between cases and controls. A total of 1,661,934 high-quality pyrosequencing reads was obtained to evaluate bacterial diversity, and 50,246 unique sequences represented all phylotypes. The type and mean number of the genera were not different between cases and controls. However, the most predominant phyla of bacteria were significantly different between cases and controls. 3 phyla (Firmicutes, Actinobacteria, and Tenericutes) and 11 genera including Gardnerella, Ureaplasma, Achromobacter, Mycoplasma, and Bifidobacteria were significantly more prevalent in cases than in controls (P < .05). Linear discriminant analysis effect size analysis suggest the Bifidobacterium, Mycoplasma, and Fenollaria species can be potential markers for vulvodynia.

CONCLUSION

Our results suggest the differences in vaginal microbiome can be associated with the vulvodynia. Park SY, Lee ES, Lee SR, et al. Vaginal Microbiome Is Associated With Vulvodynia, Vulvar Pain Syndrome: A Case-Control Study. Sex Med 2021;9:100314.

[The role of herpesviruses in development of diseases of the urogenital tract and infertility in women]

This review presents the data on the spreading of all known human herpesviruses (НHVs) in female urogenital tract. According to the WHO almost 500 million people worldwide suffer from genital infection caused by НHVs. НHVs were detected in various inflammatory diseases of female upper and lower genital tract (vaginitis and cervicitis), in extrauterine pregnancy (in fallopian tubes), in infertility (cervical channel, endometrium and ovaries). Herpes simplex virus 1 (HSV‑1) was identified for the first time in oocytes after failed in vitro fertilization (IVF). НHVs produce negative effect on the entire reproductive process from conception to childbirth. It was established that HSV, cytomegalovirus (CMV) and human herpesvirus 6 (HHV-6) markedly increase the risk of spontaneous abortion, preterm birth and stillbirth. Intrauterine НHV infection is a major cause of congenital malformations. Data on humoral and cell immunity in genital herpesvirus infections (НHVI) are also reviewed. Intravaginal HSV‑2 infection changes cell composition of vaginal mucosa, i.e., together with cells mobilized from the blood, protective role is performed by resident memory T‑cells (TRM), natural killer cells (NK‑cells) and regulatory T‑cells (Treg) whose function consists in maintaining the balance of the activities of lymphocytes. Constant НHVI spreading is largely explained by transition of primary infection to potentially reactivating latent form, since latent virus is unavailable to immune recognition and medicines. The genome editing system CRISPR/Cas9 can recognize and modify not only active but also latent viruses. The promising pilot results with the use of this system offer the possibility of developing innovative technologies for НHV elimination and НHVI eradication.

Effect of clindamycin and a live biotherapeutic on the reproductive outcomes of IVF patients with abnormal vaginal microbiota: protocol for a double-blind, placebo-controlled multicentre trial

INTRODUCTION

Recent studies in in vitro fertilisation (IVF) patients have associated abnormal vaginal microbiota (AVM) with poor clinical pregnancy rates of 6%-9% per embryo transfer. The biological plausibility for this finding is hypothesised to be ascending infection to the endometrium which in turn hampers embryo implantation. New molecular based diagnosis may offer advantages compared to microscopical diagnosis of AVM which has huge inter-study variability ranging from 4 to 38%; however, the important question is whether screening and treatment of AVM would improve reproductive outcomes in IVF patients. Herein, we describe a protocol for an ongoing double-blind, placebo-controlled multicentre trial of IVF patients diagnosed with AVM and randomised in three parallel groups 1:1:1.

METHODS AND ANALYSIS

This is a drug intervention study where IVF patients will be screened for AVM, using a qPCR assay targeting Atopobium vaginae and Gardnerella vaginalis. If positive, patients will be randomised to one of the three study arms. The first arm consists of clindamycin 300 mg ×2 daily for 7 days followed by vaginal Lactobacillus crispatus CTV-05 until clinical pregnancy scan week 7-9. The second arm consists of clindamycin and placebo L. crispatus CTV-05, whereas patients in the third arm will be treated with placebo/placebo. We used a superiority design to estimate that active treatment in both arms will increase the primary outcome, clinical pregnancy rate per embryo transfer, from 20% to 40%. A potential difference between the two active arms was considered exploratory. With a power of 80% and an alpha at 5%, the sample size is estimated to be 333 patients randomised. A pre-planned interim analysis is scheduled at 167 patients randomised.

ETHICS AND DISSEMINATION

All patients have to give informed consent. Dissemination of results is ensured in clinical trial agreements whether they be positive or not. Ethics committee, Central Denmark Region approved this protocol.

TRIAL REGISTRATION NUMBER

ICH-GCP monitored trial, EudraCT 2016-002385-31; Pre-results.

Characterization of the Vaginal DNA Virome in Health and Dysbiosis

Bacterial vaginosis (BV) is characterized by a reduction in Lactobacillus (L.) spp. abundance and increased abundance of facultative anaerobes, such as Gardnerella spp. BV aetiology is not fully understood; however, bacteriophages could play a pivotal role in the perturbation of the vaginal bacterial community. We investigated the vaginal viral community, including bacteriophages and the association to the bacterial community and BV-status. Vaginal samples from 48 patients undergoing IVF treatment for non-female factor infertility were subjected to metagenomic sequencing of purified virus-like particles. The vaginal viral community was characterized and correlated with the BV-status by Nugent score, bacterial community, structure, and the presence of key vaginal bacterial species. The majority of identified vaginal viruses belonged to the class of double-stranded DNA bacteriophages, with eukaryotic viruses constituting 4% of the total reads. Clear links between the viral community composition and BV (q = 0.006, R = 0.26) as well as the presence of L. crispatus (q = 0.001, R = 0.43), L. iners, Gardnerella spp., and Atopobium vaginae were found (q < 0.002, R > 0.15). The eukaryotic viral community also correlated with BV-status (q = 0.018, R = 0.20). In conclusion, the vaginal virome was clearly linked with bacterial community structure and BV-status.

The Impact of Female Genital Microbiota on Fertility and Assisted Reproductive Treatments

Objective: To review publish data about human microbiome. It is known to modulate many body functions. In the field of Reproductive Medicine, the main question is in what extent may female genital tract microbiome influence fertility, both by spontaneous conception or after Assisted Reproductive Treatments (ART). The aim of this work is to review publish data about this matter. Materials and methods: This is a systematic review on the effect of the microbiota of the female genital tract on human fertility and on the outcomes of ART. Results: Fourteen articles were retrieved, concerning female lower genital tract and endometrium microbiota, including 5 case-controls studies about its impact on fertility, 8 cohort studies regarding ART outcomes and 1 mixed study. The main variables considered were richness and diversity of species, Lactobacillus dominance and the role of other bacteria. Results and conclusions of the various studies were quite diverse and incoherent. Despite the inconsistency of the studies, it seems that vaginal, cervical and endometrial microbiome may eventually play a role. Whether high richness and diversity of species, low amounts of Lactobacillus spp. or the presence of other bacteria, such as Gardnerella spp., may adversely affect reproductive outcomes is not clear. Conclusion: The influence of female genital microbiota on the ability to conceive is still unclear, due to the paucity and inconsistency of published data.

[Assessment of genital microbiota: An emerging approach in assisted reproductive techniques]

The genital microbiota actively participates in women's reproductive health. Indeed, a genital dysbiosis (microbial imbalance associated with adverse effects on host health) can lead to vaginal infections (such as mycoses or bacterial vaginosis). Recent data reported that genital dysbiosis (e.g. vaginal or endometrial) was associated with fewer chances of live births in assisted reproductive technologies (ART), via decreased pregnancy rates and an increased risk of miscarriages. The presence or diversity of certain bacterial strains (in particular Gardenellavaginalis, Proteobacteria, Lactobacillusjensenii, Lactobacilluscrispatus or Atopobiumvaginae) within the genital microbiota seem to be associated with the outcomes of ART cycles, suggesting new approaches to improve ART results. In this review, we aim at presenting the state of art on the association between the female genital microbiota and ART success. The diagnostic and therapeutic approaches (i.e. probiotics, antibiotic therapy and transplantation of vaginal microbiota) in the management of patients with altered microbiota will also be discussed. The confirmation of these data in the coming years could significantly improve the management of infertile patients in ART with a more personalized approach partially based on the female genital microbiotic profile.

Alterations in Vaginal Microbiota and Associated Metabolome in Women with Recurrent Implantation Failure

Recurrent implantation failure (RIF) refers to repeated failure to become pregnant after transferring embryos with normal morphology. However, the pathogenesis of RIF remains unrevealed, especially for those without any pathological features. In this study, we characterized the vaginal microbiota and metabolomes of patients with unexplained RIF, while patients who achieved clinical pregnancy in the first frozen embryo transfer (FET) cycle were used as controls. Based on 16S rRNA gene sequencing of the vaginal microbiota, the vaginal Lactobacillus showed a significant positive correlation with the pregnancy rate, and the RIF group presented higher microbial α-diversity than the control group (P value = 0.016). The metabolomic profile identified 2,507 metabolites, of which 37 were significantly different between the two groups (P value < 0.05, variable importance for the projection [VIP] > 1). Among them, 2',3-cyclic UMP and inositol phosphate were the top two metabolites that were higher in the RIF group, while glycerophospholipids and benzopyran were important metabolites that were lower in the RIF group. A lack of lysobisphosphatidic acid and prostaglandin metabolized from glycerophospholipids will lead to deferred implantation and embryo crowding. Benzopyran, as a selective estrogen receptor modulator, may affect the outcome of pregnancy. All of the changes in metabolite profiles may result in or from the differential microbiota compositions in RIF patients. In conclusion, significant differences were presented in the vaginal microbiota and metabolomes between patients with unexplained RIF and women who became pregnant in the first FET cycle. For the first time, this study elaborates the possible pathogenesis of RIF by investigating the vaginal microbiota and metabolites in RIF patients.IMPORTANCEIn vitro fertilization-embryo transfer (IVF-ET) is now widely applied for treating infertility, and unexplained recurrent implantation failure (RIF) has become a substantial challenge. We hypothesize that vaginal microbial dysbiosis is associated with RIF, as it is linked to many female reproductive diseases. In this study, we characterized the vaginal microbiota and metabolomes of patients with unexplained RIF, while patients who achieved clinical pregnancy in the first IVF cycle were set as controls. In general, significant differences were discovered in the vaginal microbiota and metabolomes between the two groups. This study is the first detailed elaboration of the vaginal microbiota and metabolites associated with RIF. We believe that our findings will inspire researchers to consider the dynamics of microbiomes related to the microenvironment as a critical feature for future studies of nosogenesis not only for RIF but also for other reproductive diseases.

Association of the eukaryotic vaginal virome with prophylactic antibiotic exposure and reproductive outcomes in a subfertile population undergoing in vitro fertilisation: a prospective exploratory study

OBJECTIVE

The objective of this study was to use high-throughput sequencing to describe the vaginal eukaryotic DNA virome in patients undergoing in vitro fertilisation (IVF) to examine associations between the vaginal virome, antibiotic exposure and IVF outcomes.

DESIGN

Prospective exploratory study.

SETTING

Single academic fertility centre.

POPULATION

Subfertile women age 18-43 years undergoing their first IVF cycle with a fresh embryo transfer.

METHODS

The primary exposure was prophylactic azithromycin or no azithromycin before IVF. A mid-vaginal swab was obtained at the time of embryo transfer for virome analysis.

MAIN OUTCOME MEASURES

The primary outcomes compared between exposure groups were characteristics of vaginal virome and clinical pregnancy rates. Secondary outcomes were virome associations with number of oocytes retrieved, number of blastocysts and implantation rate.

RESULTS

Twenty-six women contributed a vaginal swab before embryo transfer. There were no significant differences in IVF outcomes between azithromycin groups. There was no association between viral diversity and clinical pregnancy overall. A higher diversity of herpesviruses and α-papillomaviruses was observed in samples from the azithromycin-treated group compared with the no azithromycin group (P = 0.04). In women that received azithromycin, viral diversity was higher in the group that did not achieve clinical pregnancy compared with those who did (P = 0.06).

CONCLUSIONS

We demonstrate that the vaginal eukaryotic virome in women undergoing IVF is associated with antibiotic exposure. Additionally, we demonstrate an inverse trend between viral diversity and pregnancy, with a higher number of viruses detected associated with failure to achieve clinical pregnancy in the azithromycin group.

TWEETABLE ABSTRACT

Higher viral diversity is associated with prophylactic antibiotic exposure in subfertile women undergoing IVF.

Characterization of Microbiota in Endometrial Fluid and Vaginal Secretions in Infertile Women with Repeated Implantation Failure

Studies suggest that persisting intrauterine bacterial infectious conditions such as chronic endometritis potentially impair the embryo implantation process. The microbial environment in the female reproductive tract, however, remains largely undetermined in infertile patients with a history of repeated implantation failure (RIF). Using next-generation sequencing, we aimed to characterize the microbiota in the endometrial fluid (EF) and vaginal secretions (VS) in women with RIF. Twenty-eight infertile women with a history of RIF and eighteen infertile women undergoing the first in vitro fertilization-embryo transfer attempt (the control group) were enrolled in the study. On days 6-8 in the luteal phase of the natural, oocyte-pickup, or hormone replacement cycle, the paired EF and VS samples were obtained separately. Extracted genomic DNA was pyrosequenced for the V4 region of 16S ribosomal RNA using a next-generation sequencer. The EF microbiota had higher α-diversity and broader bacterial species than the VS microbiota both in the RIF and control groups. The analysis of the UniFrac distance matrices between EF and VS also revealed significantly different clustering. Additionally, the EF microbiota, but not the VS microbiota, showed significant variation in community composition between the RIF group and the control group. Burkholderia species were not detected in the EF microbiota of any samples in the control group but were detectable in a quarter of the RIF group. To our best knowledge, this is the first study investigating the microbiota in the paired EF and VS samples in infertile women with RIF.