The Role of Genital Tract Microbiome in Fertility: A Systematic Review

A multiple male and female pregnancy in a patient with stage IV endometriosis undergoing single embryo transfer after IVF-ICSI

Olcha P et al., 2025 · Ginekologia polska · Free to read

Polycystic Ovary Syndrome and Oxidative Stress-From Bench to Bedside

Zeber-Lubecka N et al., 2023 · International Journal of Molecular Sciences · Free full text on PubMed Central

Myo-inositol supplementation to prevent gestational diabetes in overweight non-obese women: bioelectrical impedance analysis, metabolic aspects, obstetric and neonatal outcomes - a randomized and open-label, placebo-controlled clinical trial

Vitale SG et al., 2020 · Int J Food Sci Nutr

This study aims to evaluate the effects of myo-inositol supplementation on gestational diabetes mellitus (GDM) rates and body water distribution in overweight non-obese women. 223 overweight non-obese women pregnant were randomly assigned to the treatment group (2 g of myo-inositol plus 200 µg of folic acid) or to the placebo one (200 µg of folic acid). The treatment lasted until three weeks after delivery. A tetrapolar impedance analyser was used to study body composition. The incidence of GDM was significantly reduced in the myo-inositol group compared with the placebo group. There was a significant increase in TBW, ECW and ICW values in the placebo group compared to the myo-inositol group. We have recorded a significant reduction in the overall incidence of pregnancy-induced hypertension in the myo-inositol group compared with the placebo group. Our results demonstrate the effectiveness of myo-inositol supplementation in preventing GDM in overweight non-obese pregnant women.

Non-hormonal mediators of uterine fibroid growth

Cetin E et al., 2020 · Current opinion in obstetrics & gynecology · Free full text on PubMed Central

Uterine fibroids are the most common benign neoplasms of the female reproductive tract and one of the major public health concerns. Although most women with uterine fibroids are asymptomatic, over 30% of them will present with varying symptoms. This review focuses on the role of non-hormonal mediators and pathways in uterine fibroid biology. Furthermore, it provides data regarding the most recent findings in the field of compounds, which use those non-hormonal pathways in the medical therapy of uterine fibroids. Complex signaling pathway alterations are crucial for uterine fibroid development. The topic of the pathophysiology of uterine fibroids focuses mostly on steroids and other hormones. However, other very important pathways exist, and some of them are independent of hormones. Some of the most important pathways, which are non-hormonal, but in some cases still hormone-depended, include growth factors, cytokines and inflammation, Smad proteins, wingless type/β-catenin and others. Much more is known about hormonal than about non-hormonal signaling in uterine fibroids. Growth factors, early life exposure and inflammation are key factors in uterine fibroid biology. Numerous agents depend on those pathways and may find their place in the current and future therapy of uterine fibroids.

The microbiota continuum along the female reproductive tract and its relation to uterine-related diseases

Chen C et al., 2017 · Nat Commun · Free full text on PubMed Central

Reports on bacteria detected in maternal fluids during pregnancy are typically associated with adverse consequences, and whether the female reproductive tract harbours distinct microbial communities beyond the vagina has been a matter of debate. Here we systematically sample the microbiota within the female reproductive tract in 110 women of reproductive age, and examine the nature of colonisation by 16S rRNA gene amplicon sequencing and cultivation. We find distinct microbial communities in cervical canal, uterus, fallopian tubes and peritoneal fluid, differing from that of the vagina. The results reflect a microbiota continuum along the female reproductive tract, indicative of a non-sterile environment. We also identify microbial taxa and potential functions that correlate with the menstrual cycle or are over-represented in subjects with adenomyosis or infertility due to endometriosis. The study provides insight into the nature of the vagino-uterine microbiome, and suggests that surveying the vaginal or cervical microbiota might be useful for detection of common diseases in the upper reproductive tract.Whether the female reproductive tract harbours distinct microbiomes beyond the vagina has been a matter of debate. Here, the authors show a subject-specific continuity in microbial communities at six sites along the female reproductive tract, indicative of a non-sterile environment.

Chronic endometritis and infertility

Park HJ et al., 2017 · Clin Exp Reprod Med · Free full text on PubMed Central

Chronic endometritis (CE) is a condition involving the breakdown of the peaceful co-existence between microorganisms and the host immune system in the endometrium. A majority of CE cases produce no noticeable signs or mild symptoms, and the prevalence rate of CE has been found to be approximately 10%. Gynecologists and pathologists often do not focus much clinical attention on CE due to the time-consuming microscopic examinations necessary to diagnose CE, its mild clinical manifestations, and the benign nature of the disease. However, the relationship between CE and infertility-related conditions such as repeated implantation failure and recurrent miscarriage has recently emerged as an area of inquiry. In this study, we reviewed the literature on the pathophysiology of CE and how it may be associated with infertility, as well as the literature regarding the diagnosis and treatment of CE. In addition, we discuss the value of hysteroscopic procedures in the diagnosis and treatment of CE.

Male Tract Microbiota and Male Infertility

Grande G et al., 2024 · Cells · Free full text on PubMed Central

In recent years, several studies have analyzed the composition of the male genital tract microbiota and its changes in infertility or in different situations associated with infertility. The aim of this narrative review is to obtain more insight on this topic; in particular, to describe actual evidence about changes in the semen microbiota in patients with infertility, male tract infections, or HPV infections. In semen, an increase in semen Prevotella spp. is associated with oligozoospermia and with obesity-associated asthenozoospermia; an increase in Pseudomonas is more frequently associated with asthenozoospermia and oligozoospermia; a reduction in Lactobacilli spp. (namely in Lactobacillus crispatus) may represent a marker of low semen quality. However, an increase in Lactobacillus iners is considered a risk factor for a reduced sperm concentration. In patients with prostatitis, there is a reduction in Lactobacillus spp. and an increase in Streptococcus spp., opening important perspectives about the role of probiotic treatments in these patients. Finally, an increase in Fusobacteria spp. was observed in patients with an HPV infection. In the conclusion, we underline the interactions between the seminal and vaginal microbiota, so that further studies should focus on the "couple genital microbiota".

Gut Dysbiosis in Selected Gynecological Diseases Associated with Female Infertility: A Scoping Review

Nowakowski Ł et al., 2026 · Journal of clinical medicine · Free full text on PubMed Central

Background/Objectives: Female infertility represents a significant public health issue. Available evidence supports the hypothesis that the gut microbiota may play an essential role in women's reproductive health and may serve as a diagnostic or prognostic biomarker in specific gynecological disorders. A substantial part of current research concerns disturbed communication between the hypothalamic-pituitary-ovarian axis and the gut microbiota, providing the basis for analyzing this phenomenon as the gut-ovary axis or the gut-vagina-ovary axis. The primary aim of this scoping review was to map the available evidence on the relationship between gut microbiota composition and female infertility, with particular emphasis on polycystic ovary syndrome (PCOS, currently polyendocrine metabolic ovarian syndrome, PMOS) endometriosis, and uterine fibroids. The review was conducted in accordance with the PRISMA Extension for Scoping Reviews (PRISMA-ScR). PubMed, Scopus, and Google Scholar were searched using terms related to gut microbiota, female infertility, PCOS, endometriosis, and uterine leiomyomas. Peer-reviewed publications in English published between 2015 and 2025 were considered. The included studies were descriptively synthesized to identify recurring microbiota patterns and research gaps. The reviewed evidence indicates that gut dysbiosis may be associated with selected gynecological disorders affecting fertility, including PCOS, endometriosis, and uterine fibroids. The gut microbiome may have potential value as a biomarker supporting diagnosis, treatment selection, and prognosis. The gut microbiome represents a promising but still insufficiently validated area in the management of gynecological diseases associated with female infertility. Further high-quality clinical studies are needed to verify the effectiveness of microbiome-based therapies and to develop evidence-based guidelines for managing infertility associated with gut dysbiosis.