Vaginal microbiome changes with levonorgestrel intrauterine system placement

The association between lifestyle factors and the composition of the vaginal microbiota: a review

PURPOSE

The vaginal microbiota offers valuable insights into women's sexual health and the risk of developing sexually transmitted infections (STIs) and bacterial vaginosis. Despite the public health implications of changes in the vaginal environment, existing data on this topic remain sparse.

METHODS

Following the PRISMA statement guidelines, we consulted five bibliographic databases, focusing on five main daily habits and behaviors. We included only studies published up to October 2023, investigating the influence of personal hygiene, sexual behaviors, hormonal contraception, smoking, alcohol consumption, and psychosocial stress on the vaginal microbiota using next-generation sequencing.

RESULTS

Based on our inclusion criteria, we incorporated 37 studies into this review. Hormonal contraception and personal hygiene were found to promote eubiosis of the vaginal microbiota. In contrast, sexual behaviors, smoking, alcohol consumption, and psychosocial stress were associated with an increased susceptibility to bacterial vaginosis, STIs, and severe pelvic inflammatory diseases due to a modified vaginal microbiota. Black ethnicity emerged as a confounding factor, with this population showing unstable vaginal microbiota. Oral contraception and a stable male sexual partner were found to favor Lactobacillus colonization, acting as a protective factor. Conversely, non-hormonal contraception and unprotected or non-penile/vaginal sexual activity increased the incidence of vaginal inflammation and bacterial vaginosis by disturbing the vaginal microbiota and reducing Lactobacillus abundance.

CONCLUSION

Daily habits and lifestyle can influence the composition of the vaginal microbiota, thereby affecting vaginal health. Disturbances in the vaginal microbiota could be associated factors for STIs and vaginosis. Therefore, prioritizing more appropriate management of the vaginal microbiota is crucial.

The reproductive microbiome in dogs: Friend or foe?

The microbiome of the reproductive tract is an area of research in full development. Specifically, the microbiome may be involved in reproductive health, disease, and pregnancy outcomes, as has been shown in humans and animals, including dogs. The aim of the present review was to summarize current knowledge on the microbiome of the canine reproductive tract, to expose the controversial role that some bacterial agents may play in canine subfertility, and to highlight future research perspectives. This review discussed whether the use of antimicrobials in dogs is appropriate to increase reproductive performance and to treat subfertility without proper diagnosis, and the possible use of probiotics to modulate the reproductive canine microbiome. Finally, we indicate areas in which scientific knowledge is currently lacking, and could be promising directions for future research.

The effect of the female genital tract and gut microbiome on reproductive dysfunction

Microorganisms are ubiquitous in the human body; they are present in various areas including the gut, mouth, skin, respiratory tract, and reproductive tract. The interaction between the microbiome and reproductive health has become an increasingly compelling area of study. Disruption of the female genital tract microbiome can significantly impact the metabolism of amino acids, carbohydrates, and lipids, increasing susceptibility to reproductive tract diseases such as vaginitis, chronic endometritis, endometrial polyps, endometriosis, and polycystic ovary syndrome. The gut microbiome, considered an endocrine organ, plays a crucial role in the reproductive endocrine system by interacting with hormones like estrogen and androgens. Imbalances in the gut microbiome composition can lead to various diseases and conditions, including polycystic ovary syndrome, endometriosis, and cancer, although research on their mechanisms remains limited. This review highlights the latest advancements in understanding the female genital tract and gut microbiomes in gynecological diseases. It also explores the potential of microbial communities in the treatment of reproductive diseases. Future research should focus on identifying the molecular mechanisms underlying the association between the microbiome and reproductive diseases to develop new and effective strategies for disease prevention, diagnosis, and treatment related to female reproductive organs.

Contraceptive effects on the cervicovaginal microbiome: Recent evidence including randomized trials

BACKGROUND

Until recently, most data regarding the effects of non-barrier contraceptives on the mucosal microbiome have derived from observational studies, which are potentially biased due to behavioral confounders that may mask their true biological effects.

METHOD OF STUDY

This narrative review summarises recent evidence of the effect of contraceptives on the cervicovaginal microbiome, emphasising data obtained through randomized trials.

RESULTS

Good quality data describe that initiation of long-acting progestin-only contraceptives, including levonorgestrel (LNG)-implant and the injectables depot-medroxyprogesterone acetate (DMPA-IM) and norethisterone enanthate (NET-EN) do not alter the mucosal microbial environment. Likewise, no strong evidence exists that the use of oral contraceptive pills (OCPs) is associated with alterations of the vaginal microbiome or increased risk of bacterial sexually transmitted infections (STIs). Limited data on the effect of intravaginal rings (IVRs) on the mucosal environment exist and show conflicting effects on the vaginal microbiota. Copper intrauterine device (Cu-IUD) initiation has been associated with bacterial vaginosis (BV) acquisition, including in a randomized trial. LNG-IUDs may have similar affects but need to be evaluated further.

CONCLUSION

Different synthetic hormones have divergent effects on the microbiome and therefore novel hormonal methods need to be rigorously evaluated. Furthermore, the addition of antiretrovirals into multipurpose technologies may alter the effects of the hormonal component. There is thus a critical need to improve our understanding of the biological effects of contraceptive hormones and delivery methods with different pharmacokinetic and chemical properties on the mucosal microbiome in rigorous trials, to inform the development of novel contraceptives and improve individual family planning guidance.

Lactobacillus-dominance and rapid stabilization of vaginal microbiota in combined oral contraceptive pill users examined through a longitudinal cohort study with frequent vaginal sampling over two years

BACKGROUND

Bacterial vaginosis (BV), a condition in which vaginal Lactobacillus spp. are in low abundance, is associated with vulvovaginal symptoms, obstetric outcomes and urogenital infections. Recurrent BV is difficult to manage, and emerging data indicate a reduced risk of BV with the use of hormonal contraception (HC). Despite widespread use, little longitudinal data is available on whether, and in what timeframe, combined oral contraceptive pills (COCs) may act to affect vaginal microbiota stability and Lactobacillus dominance.

METHODS

We compared the vaginal microbiota of reproductive-age cisgender women during intervals on combined estrogen and progestin COCs with non-use intervals in a 2-year observational study. Vaginal microbiota were characterized by 16S rRNA gene amplicon sequencing.

FINDINGS

COC users were more likely to have Lactobacillus-dominated microbiota and more stable microbiota over time. Stability increased and then plateaued four weeks after COC initiation. The associations between COCs and Lactobacillus spp. dominance, and microbiota stability, were statistically significant for White, but not African American women; however sample size was limited for African American participants. Findings were similar for other forms of HC and when excluding samples collected during menses.

INTERPRETATION

Our study provides a methodologic framework to evaluate observational longitudinal microbiota data with exposure crossovers. We found COCs are associated with vaginal microbiota stability and a Lactobacillus-dominated state. COCs appear to impact stability within a month of initiation. Our findings have clinical implications for how soon benefits can be expected in (at least White) patients initiating COCs, and support the need for larger prospective trials to verify our results in ethnically diverse populations.

FUNDING

R01-AI089878.

Roles of the Microbiota of the Female Reproductive Tract in Gynecological and Reproductive Health

The microbiome of the female reproductive tract defies the convention that high biodiversity is a hallmark of an optimal ecosystem. Although not universally true, a homogeneous vaginal microbiome composed of species of Lactobacillus is generally associated with health, whereas vaginal microbiomes consisting of other taxa are generally associated with dysbiosis and a higher risk of disease. The past decade has seen a rapid advancement in our understanding of these unique biosystems. Of particular interest, substantial effort has been devoted to deciphering how members of the microbiome of the female reproductive tract impact pregnancy, with a focus on adverse outcomes, including but not limited to preterm birth. Herein, we review recent research efforts that are revealing the mechanisms by which these microorganisms of the female reproductive tract influence gynecologic and reproductive health of the female reproductive tract.

Challenges in Clinical Diagnosis and Management of Chronic Endometritis

Chronic endometritis (CE) is a local mucosal infectious and inflammatory disorder characterized by unusual filtration of CD138(+) endometrial stromal plasmacytes. CE is attracting attention due to its potential association with infertility of unknown etiology, repeated implantation failure, recurrent pregnancy loss, and several maternal/neonatal complications. Due to the variance in study design among researchers, universal diagnostic criteria remain to be established for the clinical diagnosis and management of CE. This review article aims to summarize current knowledge and provide insights into unsolved questions on CE to establish clinical guidelines for the disease from the viewpoint of human reproduction.

Association between progesterone treatment and neonatal outcome in preterm births: a retrospective analysis

This retrospective study was conducted to determine if infants born prematurely despite prophylactic maternal progesterone treatment during pregnancy may still benefit from its adjunct properties and have decreased neonatal complications. 248 women treated with vaginal/intramuscular progesterone during pregnancy and 2519 controls who gave birth to a preterm newborn (24 + 0-36 + 6 gestational weeks) at a tertiary medical centre in 2012-2019. The primary outcome measure was neonatal infectious composite outcome. Secondary outcome measures were other maternal and neonatal complications. Compared to controls, the study group was characterised by lower gestational age at birth (35.0 ± 2.66 vs. 36.0 ± 2.23 weeks, p < .001), lower birth weight (2294 vs. 2485 g, p < .001), higher rates of neonatal infectious composite outcome (27.82 vs. 21.36%, p = 0.024), NICU admission, periventricular leukomalacia, and mechanical ventilation. The higher neonatal infectious composite outcome is likely associated with the lower gestational age at birth in this high-risk group and not the progesterone treatment per se.IMPACT STATEMENTWhat is already known on this subject? Several randomised controlled trials have shown that progesterone administration in pregnancy significantly reduced the rate and complications of preterm birth. A recent study reported that vaginal administration of progesterone during pregnancy was more effective than intramuscular administration in decreasing vaginal group B Streptococcus (GBS) colonisation. This finding raises the question of whether progesterone treatment may have additional benefits besides preventing preterm birth and may reduce neonatal complication rate in preterm infants.What do the results of this study add? This is the first study examining the impact of gestational progesterone exposure on outcomes of preterm infants. The primary objective was a composite measure of infectious neonatal outcomes. Newborns who had progesterone exposure on average had lower gestational age, lower birth weight and higher neonatal infectious composite outcome. The significant difference is explained by lower gestational age.What are the implications of these findings for clinical practice and/or further research? Progesterone is widely used to prevent preterm birth, and may have important additive effects even when prematurity is not avoided. Although the findings did not support our initial hypothesis, they warrant further examination with larger cohorts.

The Effect of Exogenous Sex Steroids on the Vaginal Microbiota: A Systematic Review

Background

Exogenous sex steroids within hormonal contraception and menopausal hormone therapy (MHT) have been used for family planning and management of menopausal symptoms, without consideration of their effects on the vaginal microbiota. This is largely because their use predates our understanding of the importance of the vaginal microbiome on human health. We conducted a systematic review (PROSPERO: CRD42018107730) to determine the influence of exogenous sex steroids, stratified by oestrogen-containing or progestin-only types of contraception, and MHT on the vaginal microbiome, as measured by molecular methods.

Methods

Embase, PubMed and Medline were searched for relevant literature published through to December 1st 2020. Eligible studies reported on the effect of specific exogenous sex steroids on the vaginal microbiome using a molecular method. Data regarding the ‘positive’, ‘negative’ or ‘neutral’ effect of each type of contraceptive or MHT on the vaginal microbiome was extracted and summarised. A positive effect reflected sex steroid exposure that was associated with increased abundance of lactobacilli, a change to, or maintenance of, an optimal vaginal microbiota composition, or a decrease in bacterial diversity (specifically reflecting a low-diversity optimal microbiota state), relative to the control group. An exogenous sex steroid was designated as having a negative effect on the vaginal microbiome if it resulted in opposing effects (i.e. loss of lactobacilli, a non-optimal microbiota state). When no significant change was found, this was considered neutral/inconclusive.

Results

We identified 29 manuscripts reporting on the effect of exogenous sex steroids on the vaginal microbiome; 25 investigating hormonal contraceptives, and 4 investigating MHT. Oestrogen-containing contraception, particularly reflecting the combined oestrogen and progestin-containing contraceptive pill, had a positive effect on the composition of the vaginal microbiota. Progestin-only contraception, particularly reflecting depo-medroxyprogesterone acetate, had mixed effects on the microbiota. Among post-menopausal women using MHT, exogenous oestrogen applied topically was associated with increased prevalence of lactobacilli.

Conclusion

Our findings suggest that oestrogen-containing compounds may promote an optimal vaginal microbiota, which could have clinical applications. The impact of progestin-only contraceptives on the vaginal microbiota is less clear; more data is needed to determine how progestin-only contraceptives contribute to adverse reproductive and sexual health outcomes.

THE CAPACITY OF PHYSICAL THERAPY FOR REPEATED IMPLANTATION FAILURES IN IVF PROGRAMS: A LITERATURE REVIEW

Relevance: Studies of the etiology and pathogenesis of implantation failures, both repeated and primary, as well as the possibilities of therapy today carry many contraversions. However, in recent years, numerous studies have demonstrated the high effectiveness of various physiotherapy methods in improving reproductive outcomes, including therapy and overcoming repeated implantation failures in in-vitro fertilization programs. The purpose of the study was to study the capacity of physical therapy for repeated implantation failures in in-vitro fertilization programs. Materials and Methods: The capacity of physical therapy for repeated implantation failures in in-vitro fertilization programs were studied through the search and analysis of the scientific sources for 1995-2021, available in the Scopus and Pubmed databases, using the keywords “in-vitro fertilization,” “repeated implantation failure,” “assisted reproductive technology,” and «physiotherapy.» Results: Electrical impulse therapy has established itself as the most studied method in the treatment of disorders of endometrial receptivity with proven efficacy. Physical methods of exposure can improve reproductive outcomes through a beneficial effect on the angiogenesis and architectonics of the endometrium, improving its receptivity, and normalizing physiology. Further detailed study of the etiology, pathogenetic mechanisms, as well as the effectiveness of overcoming repeated implantation failures by various methods is needed to develop treatment protocols.

Elevated Risk of Bacterial Vaginosis Among Users of the Copper Intrauterine Device: A Prospective Longitudinal Cohort Study

BACKGROUND

Limited evidence suggests that the nonhormonal contraceptive copper intrauterine device (Cu-IUD) may increase bacterial vaginosis (BV) risk, possibly due to increased volume and duration of menses, a common side effect of Cu-IUD use. Although increases in bleeding typically resolve within 6-12 months following initiation, evaluations of the association between Cu-IUD and BV have not included more than 6 months of follow-up.

METHODS

This secondary analysis of a human immunodeficiency virus type 1 prevention trial included 2585 African women ages 18-45 followed for up to 33 months. Women reported contraceptive use each month. BV was evaluated by Nugent score in 6-monthly intervals and, if clinically indicated, by Amsel criteria. Andersen-Gill proportional hazards models were used to (1) evaluate BV risk among Cu-IUD users relative to women using no/another nonhormonal contraceptive and (2) test changes in BV frequency before, while using, and following Cu-IUD discontinuation.

RESULTS

BV frequency was highest among Cu-IUD users at 153.6 episodes per 100 person-years (95% confidence interval [CI]: 145.2, 162.4). In adjusted models, Cu-IUD users experienced 1.28-fold (95% CI: 1.12, 1.46) higher BV risk relative to women using no/another nonhormonal contraception. Compared to the 6 months prior to initiation, BV risk was 1.52-fold (95% CI: 1.16, 2.00) higher in the first 6 months of Cu-IUD use and remained elevated over 18 months of use (P < .05). Among women who discontinued Cu-IUD, BV frequency was similar to pre-initiation rates within 1 year.

CONCLUSIONS

Cu-IUD users experienced elevated BV risk that persisted throughout use. Women and their providers may wish to consider BV risk when discussing contraceptive options.

The effect of different contraceptive methods on the vaginal microbiome

Introduction: Following a historical overview, the effect of different contraceptive methods on vaginal microbiome has been reviewed and summarized.Areas covered: Effects of combined hormonal contraceptives (oral or vaginal) and of progestin only (injectable and implantable), intrauterine devices/systems (copper- or levonorgestrel-releasing), on vaginal microbiome. In addition, mention is made of vaginal rings releasing antiviral drugs and lactic acid.Expert opinion: The vaginal microbiota (VM) is unique in that it is normally dominated by Lactobacillus species providing a degree of protection against infections; this however may vary, depending on the species and strains of Lactobacillus. Bacterial Vaginosis represents the most common dysbiosis of the VM and its prevalence can be influenced by use of contraception. Available evidence indicates that, under the influence of oral or systemically administered female sex hormones, there is apromotion of vaginal eubiosis, with aprevalence of ahealthy VM in which Lactobacilli predominate.

Liquid-based cervical cytology and microbiological analyses in women using cooper intrauterine device and levonorgestrel-releasing intrauterine system

OBJECTIVE

To assess the influence of the copper IUD and LNG-IUS on liquid-based cytology results (cellular atypia, reactive alterations, and microbiology).

STUDY DESIGN

This cross-sectional study was performed between January 2012 and December 2017 in the Northeast of Brazil. Three study groups, the LNG-IUS group (n = 1179), copper IUD group (n = 519), and a control group of women not using contraception (n = 14,616) were compared. To facilitate this analysis, the LNG-IUS and IUD groups were further divided into less and more than two years of use.

RESULTS

The mean age of the LNG-IUS and IUD groups was around 36 years and the control group was about 35 years (p = ns). The meantime between dispositive placement and examination was 19 ± 16 months for the LNG-IUS and 17 ± 15 months for the IUD. The frequency of epithelial atypia revealed upon cytological analysis did not differ between the groups. However, inflammatory infiltrates were significantly more frequent in the LNG-IUS and IUD (OR IUD = 1.32; OR LNG-IUS = 1.79) groups relative to control. Candida and cytolysis were more frequent in the LNG-IUS group (OR = 4.73 and 2.41, respectively) compared to both other groups. Bacterial vaginosis andActinomyces sp occurred more frequently in the IUD group (OR = 1.39 and 3352.55, respectively) compared to both other groups. Bacterial vaginosis was more common when using an IUD for more than two years than for less than two years (OR = 2.55). The Actinomyces morphotype was also observed at greater frequency after two years of IUD use than before (OR = 5.35).

CONCLUSIONS

The LNG-IUS and copper IUD do not affect the incidence of cellular atypia but do interfere with the microbiota over time. Specifically, the copper IUD is associated with bacterial vaginosis andActinomyces sp infection while the LNG-IUS is associated with candidiasis and cytolysis.

Female Gut and Genital Tract Microbiota-Induced Crosstalk and Differential Effects of Short-Chain Fatty Acids on Immune Sequelae

The gut and genital tract microbiota of females represent very complex biological ecosystems that are in continuous communication with each other. The crosstalk between these two ecosystems impacts host physiological, immunological and metabolic homeostasis and vice versa. The vaginal microbiota evolved through a continuous translocation of species from the gut to the vagina or through a mother-to-child transfer during delivery. Though the organisms retain their physio-biochemical characteristics while in the vagina, the immune responses elicited by their metabolic by-products appear to be at variance with those in the gut. This has critical implications for the gynecological, reproductive as well as overall wellbeing of the host and by extension her offspring. The homeostatic and immunomodulatory effects of the bacterial fermentation products (short chain fatty acids, SCFAs) in the gut are better understood compared to the genital tract. While gut SCFAs prevent a leakage of bacteria and bacterial products from the gut in to circulation (leaky gut) and consequent systemic inflammation (anti-inflammatory/protective role); they have been shown to exhibit dysbiotic and proinflammatory effects in the genital tract that can lead to unfavorable gynecological and reproductive outcomes. Therefore, this review was conceived to critically examine the correlation between the female gut and genital tract microbiota. Secondly, we explored the metabolic patterns of the respective microbiota niches; and thirdly, we described the diverse effects of products of bacterial fermentation on immunological responses in the vaginal and rectal ecosystems.

Hormonal Contraception and Vaginal Infections Among Couples Who Are Human Immunodeficiency Virus Serodiscordant in Lusaka, Zambia

OBJECTIVE

To examine the relationship between hormonal contraception and vaginal infections with bacterial vaginosis, vaginal candidiasis, or trichomoniasis.

METHODS

Couples who were human immunodeficiency virus (HIV) serodiscordant in Zambia were enrolled in a longitudinal cohort study. From 1994 to 2002, both partners were seen quarterly and received physical exams including genital examinations. Separate rates for three outcome infections of interest (bacterial vaginosis, vaginal candidiasis, and trichomoniasis) were calculated. Bivariate associations between baseline and time-varying covariates and outcome infections of interest were evaluated using unadjusted Anderson-Gill survival models. Adjusted hazard ratios (aHRs) were generated using multivariable Anderson-Gill survival models that included demographic and clinical factors associated with both hormonal contraceptive use and each infection of interest.

RESULTS

There were 1,558 cases of bacterial vaginosis, 1,529 cases of vaginal candidiasis, and 574 cases of trichomoniasis over 2,143 person-years of observation. Depot medroxyprogesterone acetate (DMPA) users had significantly lower rates of trichomoniasis and bacterial vaginosis. In adjusted models, DMPA was protective for bacterial vaginosis (aHR=0.72; 95% CI 0.54-0.95), candidiasis (aHR 0.75, 95% CI 0.57-1.00) and trichomoniasis (aHR=0.43, 95% CI 0.25-0.74). Oral contraceptive pills were protective for candidiasis (aHR=0.79, 95% CI 0.65-0.97).

CONCLUSION

We confirm that DMPA use was associated with reduced rates of the three most common causes of vaginitis, and oral contraceptive pill use was associated with reduced rates of candidiasis among women in couples who were HIV discordant.

Crosstalk between Vaginal Microbiome and Female Health: A review

Microbiota plays a fundamental role in the overall development and defences of human beings. The majority of indigenous microbiota exists in a mutually beneficial relationship with their hosts, while few of these are opportunistic pathogens that can lead to life-threatening diseases and chronic infections. These microbial communities constitute the primary defence against infections induced by non-indigenous invasive organisms. Female vaginal ecosystem thought to have been shaped over the years by co-evolutionary processes occurring between the particular microbial partners and the human host. Vaginal secretions contain numerous microorganisms and the host provides them nutrients for their growth and development. Disruptions in vaginal association with the microbiomes lead to the change in the vaginal environment, which enhanced the risk of acquiring diseases including sexually transmitted infections, bacterial vaginosis, fungal infections, preterm birth etc. The focus of this review is on the detailed analysis of vaginal microbiome interplay and its overall impact on female health. The mutualistic relationship between the vagina and residing microbial species has been well described. Finally, the recent advancements in the detection of microbiome interactions with the vaginal environment have been presented.

Reactional changes in short-term levonorgestrel-releasing intrauterine system (lng-ius) use

SUMMARY OBJECTIVE: To evaluate endocervical and vaginal environment changes in women using a levonorgestrel-releasing intrauterine system (LNG-IUS). METHODS: A quasi-experimental study included sixty women who had an LNG-IUS inserted in the Family Planning Clinic of UNICAMP between April and November of 2016. Women in reproductive age, non-pregnant, without the use of antibiotics and contraceptives seeking for LNG-IUS insertion were selected for this study. All women were evaluated with regard to vaginal and endocervical pH, vaginal and endocervical Gram-stained bacterioscopy, and Pap-smear before and two months after LNG-IUS insertion. Clinical aspects such as cervical mucus, vaginal discharge, and cervical ectopy were also observed. RESULTS: After LNG-IUS insertion, there was an increase in the following parameters: endocervical pH>4.5 (p=0.02), endocervical neutrophil amount (p<0.0001), vaginal cytolysis (p=0.04). There was a decrease in vaginal discharge (p=0.01). No statistically significant changes were found in vaginal pH, neutrophils amount in the vaginal mucosa, vaginal discharge appearance, vaginal candidiasis, bacterial vaginosis, vaginal coccobacillary microbiota, cervical mucus appearance, or cervical ectopy size. CONCLUSIONS: Short-term LNG-IUS use did not increase vulvovaginal candidiasis or bacterial vaginosis, and led to diminished vaginal discharge. Notwithstanding, this device promoted reactional changes in the vaginal and endocervical environment, without modification on cervical ectopy size.

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.

Canine endometrial and vaginal microbiomes reveal distinct and complex ecosystems

The objective of this study was to characterize the normal microbiome of healthy canine vagina and endometrium and to determine the effect of the stage of estrous, on the resident microbiome. Cranial vaginal swabs and uterine biopsy samples were collected from twenty-five bitches in five different stages of estrous at elective ovariohysterectomy (OVH). Over 4 million reads of the V4 region of 16S rDNA gene were obtained and used for further analyses. A total of 317 genera belonging to 24 known phyla were identified. The endometrium was higher in bacterial diversity while the vagina was higher in richness. Proteobacteria, Bacteroidetes and Firmicutes were the most abundant phyla observed across all samples. Hydrotalea, Ralstonia, and Fusobacterium accounted for nearly 60% of the OTUs identified in the vagina while organisms identified in the endometrium were more evenly distributed. Pseudomonas, Staphylococcus, and Corynebacterium were the prominent genera in the endometrium. The microbiome of the endometrium was distinctly different from that of the vagina. There was large animal-to-animal variation. Other than the vaginal microbiome of bitches in estrus (i.e. in heat), there were no distinct clustering of the organisms based on the stage of estrous. These findings establish the presence of a resident microbiome of the endometrium throughout all stages of estrous cycle.

Case for a role of the microbiome in gynecologic cancers: Clinician's perspective

In this review, we aimed to provide insight into the microbiome and its association with endometrial and ovarian cancer and their risk factors. We reviewed the literature focusing on the relationship between the microbiome and cancer, as well as the relationship between gynecologic diseases and cancers. The human body contains different kinds of microorganisms in various body parts, which is termed the microbiome. The number of microorganisms that live in and on the human body is greater than that of the human germ and somatic cells by 10-fold. The relationship between a human and their microbiome is complex; it is also one of the most important components of homeostasis. Impairment of microbiome-host homeostasis has been associated with obesity, several cancers, preterm labor, inflammatory and allergic conditions and neurodevelopmental disorders. Direct and strong causal relationships have been established for several cancers and microorganisms, such as gastric lymphoma and Helicobacter pylori infection. Interestingly, eradication of the infectious agents has also been shown to be therapeutic. The association between cancer and the microbiome, however, is more complicated than a 1 bacteria-1 cancer model, and a shift in a healthy microbiome can result in various cancers via inflammation, change in microenvironment or DNA-damaging toxins. The human microbiome is an integral part of homeostasis. Understanding the mechanisms that cause dysbiosis will enable us to elucidate the pathways that result in malignancy and investigate new treatment modalities.

Impact of contraceptive initiation on vaginal microbiota

BACKGROUND

Data evaluating the impact of contraceptives on the vaginal microbiome are limited and inconsistent.

OBJECTIVE

We hypothesized that women initiating copper intrauterine device use would have increased bacterial vaginosis and bacterial vaginosis-associated microbes with use compared to women initiating and using hormonal contraceptive methods.

STUDY DESIGN

Vaginal swabs (N = 1047 from 266 participants seeking contraception) for Nugent score determination of bacterial vaginosis and quantitative polymerase chain reaction analyses for assessment of specific microbiota were collected from asymptomatic, healthy women aged 18-35 years in Harare, Zimbabwe, who were confirmed to be free of nonstudy hormones by mass spectrometry at each visit. Contraception was initiated with an injectable (depot medroxyprogesterone acetate [n = 41], norethisterone enanthate [n = 44], or medroxyprogesterone acetate and ethinyl estradiol [n = 40]), implant (levonorgestrel [n = 45] or etonogestrel [n = 48]), or copper intrauterine device (n = 48) and repeat vaginal swabs were collected after 30, 90, and 180 days of continuous use. Self-reported condom use was similar across all arms at baseline. Quantitative polymerase chain reaction was used to detect Lactobacillus crispatus, L jensenii, L gasseri/johnsonii group, L vaginalis, L iners, Gardnerella vaginalis, Atopobium vaginae, and Megasphaera-like bacterium phylotype I from swabs. Modified Poisson regression and mixed effects linear models were used to compare marginal prevalence and mean difference in quantity (expressed as gene copies/swab) prior to and during contraceptive use.

RESULTS

Bacterial vaginosis prevalence increased in women initiating copper intrauterine devices from 27% at baseline, 35% at 30 days, 40% at 90 days, and 49% at 180 days (P = .005 compared to marginal prevalence at enrollment). Women initiating hormonal methods had no change in bacterial vaginosis prevalence over 180 days. The mean increase in Nugent score was 1.2 (95% confidence interval, 0.5-2.0; P = .001) in women using copper intrauterine devices. Although the frequency and density of beneficial lactobacilli did not change among intrauterine device users over 6 months, there was an increase in the log concentration of G vaginalis (4.7, 5.2, 5.8, 5.9; P = .046) and A vaginae (3.0, 3.8, 4.6, 5.1; P = .002) between baseline and 30, 90, and 180 days after initiation. Among other contraceptive groups, women using depot medroxyprogesterone acetate had decreased L iners (mean decrease log concentration = 0.8; 95% confidence interval, 0.3-1.5; P = .004) and there were no significant changes in beneficial Lactobacillus species over 180 days regardless of contraceptive method used.

CONCLUSION

Copper intrauterine device use may increase colonization by bacterial vaginosis-associated microbiota, resulting in increased prevalence of bacterial vaginosis. Use of most hormonal contraception does not alter vaginal microbiota.

Associations between sexual habits, menstrual hygiene practices, demographics and the vaginal microbiome as revealed by Bayesian network analysis

The vaginal microbiome plays an influential role in several disease states in reproductive age women, including bacterial vaginosis (BV). While demographic characteristics are associated with differences in vaginal microbiome community structure, little is known about the influence of sexual and hygiene habits. Furthermore, associations between the vaginal microbiome and risk symptoms of bacterial vaginosis have not been fully elucidated. Using Bayesian network (BN) analysis of 16S rRNA gene sequence results, demographic and extensive questionnaire data, we describe both novel and previously documented associations between habits of women and their vaginal microbiome. The BN analysis approach shows promise in uncovering complex associations between disparate data types. Our findings based on this approach support published associations between specific microbiome members (e.g., Eggerthella, Gardnerella, Dialister, Sneathia and Ruminococcaceae), the Nugent score (a BV diagnostic) and vaginal pH (a risk symptom of BV). Additionally, we found that several microbiome members were directly connected to other risk symptoms of BV (such as vaginal discharge, odor, itch, irritation, and yeast infection) including L. jensenii, Corynebacteria, and Proteobacteria. No direct connections were found between the Nugent Score and risk symptoms of BV other than pH, indicating that the Nugent Score may not be the most useful criteria for assessment of clinical BV. We also found that demographics (i.e., age, ethnicity, previous pregnancy) were associated with the presence/absence of specific vaginal microbes. The resulting BN revealed several as-yet undocumented associations between birth control usage, menstrual hygiene practices and specific microbiome members. Many of these complex relationships were not identified using common analytical methods, i.e., ordination and PERMANOVA. While these associations require confirmatory follow-up study, our findings strongly suggest that future studies of the vaginal microbiome and vaginal pathologies should include detailed surveys of participants' sanitary, sexual and birth control habits, as these can act as confounders in the relationship between the microbiome and disease. Although the BN approach is powerful in revealing complex associations within multidimensional datasets, the need in some cases to discretize the data for use in BN analysis can result in loss of information. Future research is required to alleviate such limitations in constructing BN networks. Large sample sizes are also required in order to allow for the incorporation of a large number of variables (nodes) into the BN, particularly when studying associations between metadata and the microbiome. We believe that this approach is of great value, complementing other methods, to further our understanding of complex associations characteristic of microbiome research.

Effects of intrauterine contraception on the vaginal microbiota

OBJECTIVES

There have been conflicting reports of altered vaginal microbiota and infection susceptibility associated with contraception use. The objectives of this study were to determine if intrauterine contraception altered the vaginal microbiota and to compare the effects of a copper intrauterine device (Cu-IUD) and a levonorgestrel intrauterine system (LNG-IUS) on the vaginal microbiota.

STUDY DESIGN

DNA was isolated from the vaginal swab samples of 76 women using Cu-IUD (n=36) or LNG-IUS (n=40) collected prior to insertion of intrauterine contraception (baseline) and at 6 months. A third swab from approximately 12 months following insertion was available for 69 (Cu-IUD, n=33; LNG-IUS, n=36) of these women. The V4 region of the bacterial 16S rRNA-encoding gene was amplified from the vaginal swab DNA and sequenced. The 16S rRNA gene sequences were processed and analyzed using the software package mothur to compare the structure and dynamics of the vaginal bacterial communities.

RESULTS

The vaginal microbiota from individuals in this study clustered into 3 major vaginal bacterial community types: one dominated by Lactobacillus iners, one dominated by Lactobacillus crispatus and one community type that was not dominated by a single Lactobacillus species. Changes in the vaginal bacterial community composition were not associated with the use of Cu-IUD or LNG-IUS. Additionally, we did not observe a clear difference in vaginal microbiota stability with Cu-IUD versus LNG-IUS use.

CONCLUSIONS

Although the vaginal microbiota can be highly dynamic, alterations in the community associated with the use of intrauterine contraception (Cu-IUD or LNG-IUS) were not detected over 12 months.

IMPLICATIONS

We found no evidence that intrauterine contraception (Cu-IUD or LNG-IUS) altered the vaginal microbiota composition. Therefore, the use of intrauterine contraception is unlikely to shift the composition of the vaginal microbiota such that infection susceptibility is altered.

Effects of combined oral contraceptives, depot medroxyprogesterone acetate and the levonorgestrel-releasing intrauterine system on the vaginal microbiome

OBJECTIVES

Prior studies suggest that the composition of the vaginal microbiome may positively or negatively affect susceptibility to sexually transmitted infections (STIs) and bacterial vaginosis (BV). Some female hormonal contraceptive methods also appear to positively or negatively influence STI transmission and BV. Therefore, changes in the vaginal microbiome that are associated with different contraceptive methods may explain, in part, effects on STI transmission and BV.

STUDY DESIGN

We performed a retrospective study of 16S rRNA gene survey data of vaginal samples from a subset of participants from the Human Vaginal Microbiome Project at Virginia Commonwealth University. The subset included 682 women who reported using a single form of birth control that was condoms, combined oral contraceptives (COCs), depot medroxyprogesterone acetate (DMPA) or the levonorgestrel-releasing intrauterine system (LNG-IUS).

RESULTS

Women using COCs [adjusted odds ratio (aOR) 0.29, 95% confidence interval (CI) 0.13-0.64] and DMPA (aOR 0.34, 95% CI 0.13-0.89), but not LNG-IUS (aOR 1.55, 95% CI 0.72-3.35), were less likely to be colonized by BV-associated bacteria relative to women who used condoms. Women using COCs (aOR 1.94, 95% CI 1.25-3.02) were more likely to be colonized by beneficial H₂O₂-producing Lactobacillus species compared with women using condoms, while women using DMPA (aOR 1.09, 95% CI 0.63-1.86) and LNG-IUS (aOR 0.74, 95% CI 0.48-1.15) were not.

CONCLUSIONS

Use of COCs is significantly associated with increased vaginal colonization by healthy lactobacilli and reduced BV-associated taxa.

IMPLICATIONS

COC use may positively influence gynecologic health through an increase in healthy lactobacilli and a decrease in BV-associated bacterial taxa.

The Effects of Hormones and Vaginal Microflora on the Glycome of the Female Genital Tract: Cervical-Vaginal Fluid

In this study, we characterized the glycome of cervical-vaginal fluid, collected with a Catamenial cup. We quantified: glycosidase levels; sialic acid and high mannose specific lectin binding; mucins, MUC1, MUC4, MUC5AC, MUC7; and albumin in the samples collected. These data were analyzed in the context of hormonal status (day of menstrual cycle, hormonal contraception use) and role, if any, of the type of the vaginal microflora present. When the Nugent score was used to stratify the subjects by microflora as normal, intermediate, or bacterial vaginosis, several important differences were observed. The activities of four of six glycosidases in the samples from women with bacterial vaginosis were significantly increased when compared to normal or intermediate women: sialidase, P = <0.001; α-galactosidase, P = 0.006; β-galactosidase, P = 0.005; α-glucosidase, P = 0.056. Sialic acid binding sites as measured by two lectins, Maackia amurensis and Sambucus nigra binding, were significantly lower in women with BV compared to women with normal and intermediate scores (P = <0.0001 and 0.008 respectively). High mannose binding sites, a measure of innate immunity were also significantly lower in women with BV (P = <0.001). Additionally, we observed significant increases in MUC1, MUC4, MUC5AC, and MUC7 concentrations in women with BV (P = <0.001, 0.001, <0.001, 0.02 respectively). Among normal women we found that the membrane bound mucin MUC4 and the secreted MUC5AC were decreased in postmenopausal women (P = 0.02 and 0.07 respectively), while MUC7 (secreted) was decreased in women using levonorgestrel-containing IUDs (P = 0.02). The number of sialic acid binding sites was lower in the postmenopausal group (P = 0.04), but the number of high mannose binding sites, measured with Griffithsin, was not significantly different among the 6 hormonal groups. The glycosidase levels in the cervical-vaginal mucus were rather low in the groups, with exception of α-glucosidase activity that was much lower in the postmenopausal group (P<0.001). These studies present compelling evidence that the vaginal ecosystem responds to the presence of different vaginal microorganisms. These effects were so influential that it required us to remove subjects with BV for data interpretation of the impact of hormones. We also suggest that certain changes occurring in vaginal/cervical proteins are due to bacteria or their products. Therefore, the quantitation of vaginal mucins and lectin binding offers a new method to monitor bacteria-host interactions in the female reproductive tract. The data suggest that some of the changes in these components are the result of host processing, such as the increases in mucin content, while the microflora is responsible for the increases in glycosidases and the decreases in lectin binding. The methods should be considered a valid marker for insult to the female genital tract.

Vaginal Dysbiosis from an Evolutionary Perspective

Evolutionary approaches are powerful tools for understanding human disorders. The composition of vaginal microbiome is important for reproductive success and has not yet been characterized in the contexts of social structure and vaginal pathology in non-human primates (NHPs). We investigated vaginal size, vulvovaginal pathology and the presence of the main human subtypes of Lactobacillus spp./ BV-related species in the vaginal microflora of baboons (Papio spp.). We performed morphometric measurements of external and internal genitalia (group I, n = 47), analyzed pathology records of animals from 1999–2015 (group II, n = 64 from a total of 12,776), and evaluated vaginal swabs using polymerase chain reaction (PCR) (group III, n = 14). A total of 68 lesions were identified in 64 baboons. Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae, Megasphaera I, and Megasphaera II were not detected. L. jensenii, L. crispatus, and L. gasseri were detected in 2/14 (14.2%), 1/14 (7.1%), and 1/14 (7.1%) samples, respectively. BVAB2 was detected in 5/14 (35.7%) samples. The differences in the vaginal milieu between NHP and humans might be the factor associated with human-specific pattern of placental development and should be taken in consideration in NHP models of human pharmacology and microbiology.

The levonorgestrel-releasing intrauterine system is associated with delayed endocervical clearance of Chlamydia trachomatis without alterations in vaginal microbiota

Progestin-based contraception may impact women's susceptibility to sexually transmitted infection. We evaluated the effect of the levonorgestrel intrauterine system (LNG-IUS) on cervical persistence of Chlamydia trachomatis (CT) in a baboon model. Female olive baboons (Papio anubis) with or without an LNG-IUS received CT or sham inoculations. CT was detected in cervical epithelium with weekly nucleic acid amplification testing (NAAT) and culture. Presence of the LNG-IUS was associated with prolonged persistence of CT. Median time to post-inoculation clearance of CT as detected by NAAT was 10 weeks (range 7-12) for animals with an LNG-IUS and 3 weeks (range 0-12) for non-LNG-IUS animals (P = 0.06). Similarly, median time to post-inoculation clearance of CT by culture was 9 weeks (range 3-12) for LNG-IUS animals and 1.5 weeks (range 0-10) for non-LNG-IUS animals (P = 0.04). We characterized the community structure of the vaginal microbiota with the presence of the LNG-IUS to determine if alterations in CT colonization dynamics were associated with changes in vaginal commensal bacteria. Vaginal swabs were collected weekly for microbiome analysis. Endocervical CT infection was not correlated with alterations in the vaginal microbiota. Together, these results suggest that LNG-IUS may facilitate CT endocervical persistence through a mechanism distinct from vaginal microbial alterations.

Making inroads into improving treatment of bacterial vaginosis - striving for long-term cure

Bacterial vaginosis (BV) is one of the great enigmas in women's health, a common condition of unknown aetiology, which is associated with significant morbidity and unacceptably high recurrence rates. While it remains unclear whether BV recurrence is predominantly due to failure of current antibiotic regimens to eradicate BV-associated bacteria (BVAB) and biofilm, a failure of some women to re-establish a resilient Lactobacillus-dominant vaginal microbiota, reinfection from sexual partners, or a combination of these factors, it is inherently challenging to make significant inroads towards this goal. In this review, we will outline why BV is such a clinical and epidemiologic conundrum, and focus on several key approaches that we believe merit discussion and clinical research, including strategies to: i) prevent reinfection (partner treatment trials), ii) boost favourable vaginal Lactobacillus species and promote a Lactobacillus-dominant vaginal microbiome (hormonal contraceptive and probiotic trials) and iii) disrupt vaginal BV-associated biofilm.

Analysis of the Risk Factors for Aerobic Vaginitis: A Case-Control Study

AIMS

Aerobic vaginitis (AV) is a newly defined clinical entity which may interfere with women's reproductive health and have negative effects on pregnancy. This study was to identify the risk factors for AV.

METHODS

Participants in this case-control study included healthy women and women with AV. All participants completed a standardized questionnaire covering sociodemographic factors, sexual behaviors, personal hygiene habits and health behaviors. Uni- and multivariate logistic regression analyses were used for statistical evaluation.

RESULTS

A total of 290 women of reproductive age were enrolled. In the multivariate analysis, unmarried status (odds ratio [OR] 2.606, 95% confidence interval [CI] 1.257-5.402), use of an intrauterine device (OR 4.989, 95% CI 1.922-12.952), long-term use of antibiotics (OR 11.176, 95% CI 1.363-91.666) and frequent vaginal douching (OR 4.689, 95% CI 1.363-16.135) were independent risk factors for AV. On the contrary, consistent condom use (OR 0.546, 95% CI 0.301-0.991) and college-level education or above (OR 0.255, 95% CI 0.131-0.497) were independent protective factors.

CONCLUSION

Measures that may be considered to prevent AV include enhancing education to improve women's knowledge related to reproductive health, especially unmarried women, encouraging them to consistently use condoms as a contraceptive method, to avoid long-term use of antibiotics and to stop frequent vaginal douching. © 2015 S. Karger AG, Basel.