Rescue intrauterine insemination in women failing to retrieve oocytes at ovum pick-up: report of a case series.

PURPOSE: Failure to collect oocytes at the time of oocyte pick-up is an unfavorable outcome of in vitro fertilization (IVF) cycles. In these cases, prompt intrauterine insemination (IUI) could be an option (rescue IUI), but this possibility has been poorly studied. METHODS: Rescue IUI is routinely offered in our unit in women failing to retrieve oocytes, provided that they have at least one patent tube, normal male semen analysis, and the total number of developed follicles is ≤ 3. We therefore reviewed all oocyte retrievals performed from 2006 to 2022 in our unit to identify these cases. As a comparator, we referred to preplanned IUI performed during the same study period. The 95% confidence interval (95% CI) of proportions was calculated using a binomial distribution model. RESULTS: Rescue IUI was performed in 96 out of 3531 oocyte retrievals (2.7%; 95% CI 2.2-3.3%). Six live births were obtained, corresponding to 6.2% (95% CI 2.3-13.1). All pregnancies were singletons. CONCLUSIONS: Rescue IUI in women failing to retrieve oocytes is a possible option that may be considered in selected cases. The efficacy is low, but the procedure is simple, and without significant risks. Generalizability to a conventional IVF protocol setting is however limited.

Ovarian reserve does not influence natural conception: insights from infertile women.

PURPOSE: There is several albeit not univocal evidence suggesting that ovarian reserve is not related to the chance of natural pregnancy, provided that the remnant follicular pool is sufficient to ensure regular menstrual cycles. Nevertheless, available studies have some methodological limitations, and the issue cannot be considered definitively ascertained. METHODS: To further address this issue, we retrospectively selected infertile women whose infertility diagnostic work-up was unremarkable (unexplained infertility-cases) and matched them by age and study period to a group of infertile women who were diagnosed with severe male infertility (controls). If ovarian reserve impacts on natural fertility, one had to expect lower ovarian reserve among women with unexplained infertility. Tested biomarkers included AMH, AFC and day 2-3 serum FSH. The primary aim was the frequency of women with serum AMH < 0.7 ng/ml. RESULTS: Two-hundred fifty-two women with unexplained infertility and 252 women with male infertility were included. All biomarkers of ovarian reserve did not differ between the study groups. AMH levels < 0.7 ng/mL were observed in 26 (10%) women with unexplained infertility and 35 (14%) women with male infertility (p = 0.28). The adjusted OR was 0.76 (95% CI: 0.44-1.33). Significant differences did not also emerge when repeating this dichotomous analysis using other biomarkers and other thresholds for the definition of low-ovarian reserve. CONCLUSION: This study confirms that ovarian reserve is unremarkable to natural conception. Physicians and patients should be aware of this concept to avoid inappropriate counseling and undue clinical decisions.

PRRT2 benign familial infantile seizures (BFIS) with atypical evolution to encephalopathy related to status epilepticus during sleep (ESES).

PURPOSE: Heterozygous variants in PRRT2 are mostly associated with benign phenotypes, being the major genetic cause of benign familial infantile seizures (BFIS), as well as in paroxysmal disorders. We report two children from unrelated families with BFIS that evolved to encephalopathy related to status epilepticus during sleep (ESES). METHODS AND RESULTS: Two probands presented with focal motor seizures at 3 months of age, with a limited course. Both children presented, at around 5 years of age, with centro-temporal interictal epileptiform discharges with a source in the frontal operculum, markedly activated by sleep, and associated with stagnation on neuropsychological development. Whole-exome sequencing and co-segregation analysis revealed a frameshift mutation c.649dupC in the proline-rich transmembrane protein 2 (PRRT2) in both probands and all affected family members. CONCLUSION: The mechanism leading to epilepsy and the phenotypic variability of PRRT2 variants remain poorly understood. However, its wide cortical and subcortical expression, in particular in the thalamus, could partially explain both the focal EEG pattern and the evolution to ESES. No variants in the PRRT2 gene have been previously reported in patients with ESES. Due to the rarity of this phenotype, other possible causative cofactors are likely contributing to the more severe course of BFIS in our probands.

Trends in the incidence of major birth defects after assisted reproductive technologies in Lombardy Region, Northern Italy.

PURPOSE: The incidence of birth defects is increased in children born after assisted reproductive technologies (ART). However, changes in ART over time could influence this incidence. To investigate this issue, we present the frequency and trends of birth defects in ART and natural pregnancies in Lombardy, Northern Italy, during the period 2014-2020. METHODS: This is a population-based study using automated system of healthcare utilization (HCU) databases. ART pregnancies included only those obtained with conventional IVF or ICSI. After identifying the total number of deliveries, the rate of newborns with birth defects was compared between natural and ART pregnancies. A logistic regression model was used to calculate the adjusted odd ratio (OR). Analyses were repeated for every calendar year. RESULTS: Overall, 508,421 deliveries were identified, of which 14,067 (2.8%) were achieved after IVF-ICSI. A decreasing trend in birth defects over time was highlighted. The adjusted OR dropped from 1.40 (95%CI: 1.03-1.91) in 2014 to 0.92 (95%CI: 0.69-1.22) in 2020. During the study period, a significant reduction in multiple pregnancy and in the ratio of ICSI to conventional IVF was also observed, explaining at least in part the positive trend observed for birth defects. CONCLUSION: The increased risk of birth defects in children born after IVF-ICSI is not steady over time. A decline of this risk emerged in our region. Policy changes in ART may explain this beneficial effect.

Follicular steroidogenesis in random start protocols for oocyte cryopreservation.

PURPOSE: Random start protocols are commonly used for oocyte cryopreservation in women with cancer. However, albeit generally reassuring, available evidence is still insufficient to rule out a sub-optimal cycle outcome. This study aimed to compare follicular steroidogenesis between women initiating the random start protocol in the luteal phase and those initiating in the follicular phase. METHODS: Consecutive women with cancer scheduled for oocyte cryostorage were prospectively recruited. We excluded those requiring a concomitant letrozole assumption. All women received a standardized protocol with recombinant FSH and GnRH antagonists. At the time of oocyte retrieval, follicular fluids were pooled, and a sample was collected and frozen at -80 °C. All samples were assayed concomitantly after thawing by liquid chromatography-tandem mass spectrometry. The concentration of 15 different steroid hormones was determined. RESULTS: Seventy-one women were recruited. Thirty-three initiated the ovarian stimulation in the luteal phase, while the remaining 38 initiated in the follicular phase. Baseline characteristics were generally similar. Cycle outcome did also not differ; the median (interquartile range) number of frozen mature oocytes was 9 (5-14) and 10 (5-21), respectively (p = 0.42). None of the 15 tested steroid hormones differed. CONCLUSIONS: The endocrine microenvironment surrounding oocytes is not markedly influenced by the phase of the menstrual cycle at the initiation of ovarian stimulation. This result further supports the validity of random start protocols.

The impact of endometriosis on IVF efficacy: qualitative and quantitative assessment of ovarian response and embryo development.

RESEARCH QUESTION: The detrimental effects of endometriosis on IVF success are well known, but the underlying mechanisms are still uncertain. The objective of this study was to investigate the possible detrimental effects of the disease on ovarian response and embryo development. DESIGN: IVF cycles performed in the authors' unit between 2014 and 2020 were retrospectively reviewed. Women with a good ovarian reserve who underwent their first IVF cycle were included. A total of 248 women with endometriosis were identified and matched to 248 women without the disease, according to age, type of stimulation, anti-Müllerian hormone concentration and study period. The primary outcome was the number of women without good-quality embryos. Secondary outcomes included the rate of unexpected poor response (retrieval of ≤3 oocytes), the cumulative clinical pregnancy rate and the cumulative live birth rate. RESULTS: The number of women without good-quality embryos did not differ between women with endometriosis (exposed group) and those without it (unexposed group). The adjusted odds ratio was 0.85 (95% CI 0.51-1.44, P = 0.56). The clinical pregnancy rate and the live birth rate were also similar. Conversely, the rate of unexpected poor response was higher among women with endometriosis (23% versus 13%, P = 0.005). CONCLUSIONS: Overall, endometriosis does not markedly affect folliculogenesis and embryo development in the context of IVF. Only an increased risk of unexpected poor response emerged.

The role of alpha lipoic acid in female and male infertility: a systematic review.

OBJECTIVE: Infertility is an increasingly frequent health condition, which may depend on female or male factors. Oxidative stress (OS), resulting from a disrupted balance between reactive oxygen species (ROS) and protective antioxidants, affects the reproductive lifespan of men and women. In this review, we examine if alpha lipoic acid (ALA), among the oral supplements currently in use, has an evidence-based beneficial role in the context of female and male infertility. METHODS: We performed a search from English literature using PubMed database with the following keywords: 'female infertility', 'male infertility', 'semen', 'sperm', 'sub-fertile man', 'alpha-lipoic acid', ' alpha lipoic acid', 'lipoid acid', 'endometriosis', 'chronic pelvic pain', 'follicular fluid' and 'oocytes'. We included clinical trials, multicentric studies and reviews. The total number of references found after automatically and manually excluding duplicates was 180. After primary and secondary screening, 28 articles were selected. RESULTS: The available literature demonstrates the positive effects of ALA in multiple processes from oocyte maturation (0.87 ± 0.9% of oocyte in MII vs 0.81 ± 3.9%; p < .05) to fertilization, embryo development (57.7% vs 75.7% grade 1 embryo; p < .05) and reproductive outcomes. Its regular administration both in sub-fertile women and men shows to reduce pelvic pain in endometriosis (p < .05), regularize menstrual flow and metabolic disorders (p < .01) and improve sperm quality (p < .001). CONCLUSIONS: ALA represents a promising new molecule in the field of couple infertility. More clinical studies are needed in order to enhance its use in clinical practice.

Medical treatment of ovarian endometriomas: a prospective evaluation of the effect of dienogest on ovarian reserve, cyst diameter, and associated pain.

The aim of the present study was to evaluate the effect of medical treatment of ovarian endometriomas on cyst diameter, associated pain, and ovarian reserve as measured with antral follicle count (AFC) and anti-Mullerian hormone (AMH). In this prospective study, 32 patients with unilateral endometrioma associated with pelvic pain, underwent 6-month medical treatment with dienogest. Before treatment, and at the end of 6 months of treatment, patients underwent evaluation of endometrioma diameter and AFC at transvaginal ultrasonography, measurement of AMH, and evaluation of associated pain. Mean cyst diameter was 4.0 ± 1.3 cm at baseline, and 2.4 ± 1.2 cm after 6 months of treatment (p < .0001), for a reduction in diameter of 40% and a reduction in volume of 79%. Mean visual analog scale score at enrollment was 6.3 ± 2.0, with a significant improvement at 6 months (0.9 ± 1.0, p < .0001). AFC for the affected ovary improved from 4.2 ± 2.8 at baseline, to 8.6 ± 4.2 cm after 6 months (+105%; p < .0001). AMH did not change significantly from baseline (3.40 ± 2.32 ng/mL) to end of treatment (2.80 ± 1.90 ng/mL, -18%, p = .27). Medical treatment with dienogest significantly reduces endometrioma diameter and associated pain, whereas the ovarian reserve appears to be preserved, with a significant improvement of AFC and no significant change in AMH.

The Role of Different Medical Therapies in the Management of Adenomyosis: A Systematic Review and Meta-Analysis.

Background/Objectives: Adenomyosis is a benign condition characterized by the presence of endometrial tissue within the myometrium. Despite surgery being a valuable approach, medical options are considered as the first-line approach and have been investigated in the treatment of adenomyosis, although strong evidence in favor of these is still lacking. This study aims to gather all available data and determine the effectiveness of the aforementioned medical options in patients with associated pain and not currently seeking pregnancy, both in comparison to placebo and to one another. Methods: For this study, PubMed and EMBASE were used as data sources, searched up to January 2024. A systematic review and meta-analysis were performed in accordance to guidelines from the Cochrane Collaboration. The primary outcomes investigated were changes in dysmenorrhea, quantified by means of VAS scores, HMB in terms of number of bleeding days, and changes in uterine volume determined at ultrasound. Twelve eligible studies were selected. Results: The results highlighted that dienogest yields a reduction in dysmenorrhea that is significantly superior to that of the rest of the medical treatments investigated (p-value of <0.0002). On the other hand, GnRH agonists seem to play a more prominent role in reducing uterine volume (p-value of 0.003). While it was not possible to determine which medical treatment better decreased the number of bleeding days, it was observed that COC performed significantly worse than the other treatments studied (p-value of 0.02). Conclusions: While this meta-analysis provides valuable insights in the comparative efficacy of different treatments, the paucity of relevant studies on the topic might impact the reliability of some of the conclusions drawn.

Presurgical treatment of uterine myomas with the GnRH-antagonist relugolix in combination therapy: an observational study.

To evaluate if a preoperative medical treatment with the GnRH-antagonist relugolix in combination therapy in a series of patients with abnormal uterine bleeding associated with uterine myomas may correct the anemia before scheduled surgery for myoma-associated AUB. Thirty-one patients scheduled for surgery underwent a pre-operative three-month course with a daily oral tablet of 40 mg relugolix, 1 mg estradiol, and 0.5 mg norethindrone acetate. Hemoglobin levels, uterine volumes, largest myoma diameter, and VAS score for dysmenorrhea, pelvic pressure and bleeding discomfort, and indication to surgery were evaluated at study enrollment and at the end of therapy. Mean hemoglobin levels increased by 25%, from 9.3 ± 1.1 to 11.6 ± 1.7 g/dL after three months (p < 0.001). Uterine volume decreased from 380.7 ± 273.4 mL to 281.7 ± 198.7 mL (p < 0.001), whereas the diameter of the largest myoma decreased from 6.4 ± 2.8 cm to 5.5 ± 2.2 cm (p < 0.001). Four patients (13%), initially planned for a laparotomy procedure, were converted to a minimally-access procedure, whereas in eight patients (26%) surgery was avoided after medical therapy. Dysmenorrhea score improved from 4.7 ± 3.2 to 0.6 ± 1.1 (p < 0.0001). Pelvic pressure score decreased from 5.9 ± 2.1 to 3.1 ± 2.3 (p < 0.0001), whereas bleeding discomfort decreased from 7.4 ± 3.0 to 0.4 ± 1.6 (p < 0.0001). Preoperative GnRH-antagonist therapy may enhance hemoglobin levels, decrease uterine and myoma size, and alleviate symptoms, potentially enabling safe surgical procedures.

The impact of difficult embryo transfer on the success of IVF: a systematic review and meta-analysis.

The procedure of embryo transfer (ET) must be as gentle as possible since any traumatism may cause uterine contractility that interferes with the implantation. However, this ideal conduct is not always possible, and additional measures may be necessary (difficult ET). Different studies have evaluated the impact of difficult ET on the clinical pregnancy rate (CPR), but results were not univocal. The present systematic review and meta-analysis was aimed to provide a precise estimate of the possible detrimental effects of difficult ET on CPR. The study protocol was registered online (PROSPERO number: CRD42023387197). An electronic database search was performed to identify articles published until September 2022. The primary outcome was CPR. Fifteen studies fulfilled the inclusion criteria. Difficult ET significantly reduced the CPR (OR 0.70; 95%CI: 0.64-0.76; p < 0.0001. All pre-planned subgroup analyses according to study design (retrospective vs prospective studies), historical period (studies published before and after 2010), type of catheter, frequency of difficult cases (> or < 19%) and pregnancy rate (> or < 38%) confirmed the significant association. Difficult ET is associated with a significant reduction of CPR. Further studies are warranted to understand how to prevent or manage this common clinical situation.

The Efficacy of Dienogest in Reducing Disease and Pain Recurrence After Endometriosis Surgery: a Systematic Review and Meta-Analysis.

The objective of this study is to determine whether dienogest therapy after endometriosis surgery reduces the risk of recurrence compared with placebo or alternative treatments (GnRH agonist, other progestins, and estro-progestins). The design used in this study is systematic review with meta-analysis. The data source includes PubMed and EMBASE searched up to March 2022. A systematic review and meta-analysis were performed in accordance with guidelines from the Cochrane Collaboration. Keywords such as "dienogest," "endometriosis surgery," "endometriosis treatment," and "endometriosis medical therapy" were used to identify relevant studies. The primary outcome was recurrence of endometriosis after surgery. The secondary outcome was pain recurrence. An additional analysis focused on comparing side effects between groups. Nine studies were eligible, including a total of 1668 patients. At primary analysis, dienogest significantly reduced the rate of cyst recurrence compared with placebo (p < 0.0001). In 191 patients, the rate of cyst recurrence comparing dienogest vs GnRHa was evaluated, but no statistically significant difference was reported. In the secondary analysis, a trend toward reduction of pain at 6 months was reported in patients treated with dienogest over placebo, with each study reporting a significantly higher reduction of pain after dienogest treatment. In terms of side effects, dienogest treatment compared with GnRHa significantly increased the rate of spotting (p = 0.0007) and weight gain (p = 0.03), but it was associated with a lower rate of hot flashes (p = 0.0006) and a trend to lower incidence of vaginal dryness. Dienogest is superior to placebo and similar to GnRHa in decreasing rate of recurrence after endometriosis surgery. A significantly higher reduction of pain after dienogest compared with placebo was reported in two separate studies, whereas a trend toward reduction of pain at 6 months was evident at meta-analysis. Dienogest treatment compared with GnRHa was associated with a lower rate of hot flashes and a trend to lower incidence of vaginal dryness.

Intraoperative Three-Dimensional Transvaginal Ultrasound for Hysteroscopic Metroplasty: a Controlled Study.

This study aims to evaluate the role of intraoperative transvaginal three-dimensional ultrasound (3DUS) during hysteroscopic metroplasty. This is a prospective cohort of consecutive patients with septate uterus undergoing hysteroscopic metroplasty with intraoperative transvaginal 3DUS guidance compared to a historical control group of patients undergoing hysteroscopic metroplasty without 3DUS. We conducted our research in a tertiary care university hospital in Rome, Italy. This study involved nineteen patients undergoing 3DUS-guided hysteroscopic metroplasty for recurrent abortion or infertility compared to 19 age-matched controls undergoing metroplasty without 3DUS guidance. During hysteroscopic metroplasty, 3DUS was performed in the study group when the operator considered the procedure to be completed, according to standards of operative hysteroscopy. If 3DUS diagnosed a residual septum, the procedure was continued until a 3DUS diagnosis of a normal fundus was obtained. The patients were followed with a 3DUS performed 3 months after the procedure. The numbers of complete resections (residual septum absent), suboptimal resections (measurable residual septum of less than 10 mm), and incomplete resections (residual septum > 10 mm) in the intraoperative 3DUS group were compared to the numbers in the control group with no intraoperative 3DUS. At follow-up, measurable residual septa were obtained in 0% of the patients in the 3DUS-guided group versus 26% in the control group (p = 0.04). Residual septa of > 10 mm were obtained in 0% of the 3DUS group versus 10.5% in the control group (p = 0.48). Intraoperative 3DUS reduces the incidence of suboptimal septal resections at hysteroscopic metroplasty.

Expectant, Medical, and Surgical Management of Ovarian Endometriomas.

Management options for ovarian endometriomas include expectant management, medical treatment, surgical treatment, in vitro fertilization (IVF), or a combination of the above. The choice of management depends on many clinical parameters that should be taken into consideration, the first of which is the main presenting symptom. Most patients are today referred to medical therapy as a first option in the case of associated pain, and to IVF in the case of associated infertility. When both symptoms are present, usually surgery is the preferred approach. Recently, however, surgical excision of an ovarian endometrioma has been associated with a postoperative reduction in the ovarian reserve, and recent guidelines suggest that the clinician should caution the patient as to the possible damage to the ovarian reserve in the case of surgery. However, evidence has been published as to a possible detrimental effect of the ovarian endometrioma on the ovarian reserve even if expectant management is followed. In this review, the current evidence on the conservative management of ovarian endometriomas, with particular focus on the issue of the ovarian reserve, is evaluated, and the different surgical techniques for the treatment of ovarian endometriomas are discussed.

Is There a Correlation between the Second-to-Four Digit Ratio (2D:4D) and Endometriosis? Results of a Case-Control Study.

The second-to-four digit ratio (2D:4D) has been proposed as a marker of prenatal hormonal exposure. It is suggested that prenatal exposure to androgens results in a shorter 2D:4D ratio, whereas a prenatal oestrogenic environment results in a longer one. In addition, previous research has shown an association between exposure to endocrine-disrupting chemicals and 2D:4D in animals and humans. On the endometriosis side, hypothetically, a longer 2D:4D ratio, reflecting a lower androgenic intrauterine milieu, could represent an indicator of the presence of the disease. In this light, we have designed a case-control study to compare 2D:4D measurements between women with and without endometriosis. Exclusion criteria included the presence of PCOS and previous trauma on the hand that could impact the measurement of the digit ratio. The 2D:4D ratio of the right hand was measured using a digital calliper. A total of 424 participants (endometriosis n = 212; controls n = 212) were recruited. The group of cases included 114 women with endometriomas and 98 patients with deep infiltrating endometriosis. The 2D:4D ratio was significantly higher in women with endometriosis compared to controls (p = 0.002). There is an association between a higher 2D:4D ratio and the presence of endometriosis. Our results support the hypothesis claiming potential influences of intrauterine hormonal and endocrine disruptors exposure on the onset of the disease.

Mental Health among Italian Children and Adolescents during and after the SARS-CoV-2 Pandemic: A Professionals' Focus Group Study.

The SARS-CoV-2 pandemic had a negative impact on the mental health of children and adolescents. Eight focus groups and six individual hearings were conducted to gain insights from the perspectives of 97 Italian professionals from a variety of disciplines, including child and adolescent neuropsychiatrists, pediatricians, general practitioners, social workers, psychologists, teachers, school deans, non-governmental organizations, and a researcher. Urban and rural settings were represented. The present research has been promoted by the Italian Independent Authority for Children and Adolescents (Autorità Garante per l'Infanzia e l'Adolescenza, AGIA) in collaboration with the National Institute of Health (Istituto Superiore di Sanità, ISS) and the Ministry of Education and its scientific value has been supervised by a Scientific Committee. The results of the focus groups' discussions revealed increased vulnerability, with the onset of new mental health disorders in healthy individuals and those in a condition of disadvantage, migratory contexts, and with disabilities. The already critical pre-pandemic structural and operational issues of existing services have been exacerbated. In healthcare, the activation of telemedicine has been a great asset but at the same time has generated challenges and critical issues that are still unresolved. Professionals emphasized the need to pay special attention to planning integrated responses aimed at overcoming inequalities and fragmentation. The result of this initiative translates into a set of operational recommendations useful for guiding investments and policies directed toward the protection of the mental health of minors in the health, educational, and social spheres from the outset.

Fertility after Cancer: Risks and Successes.

The incidence of cancer in reproductive-aged women is 7%, but, despite the increased number of cancer cases, advances in early diagnosis and treatment have raised the survival rate. Furthermore, in the last four decades, there has been a rising trend of delaying childbearing. There has been an increasing number of couples referred to Reproductive Medicine Centers for infertility problems after one partner has been treated for cancer. In these cases, the main cause of reduced fertility derives from treatments. In this review, we describe the effects and the risks of chemotherapy, radiotherapy, and surgery in women with cancer, and we will focus on available fertility preservation techniques and their efficacy in terms of success in pregnancy and live birth rates.

Folliculogenesis in random start protocols for oocytes cryopreservation: quantitative and qualitative aspects.

Random start protocols are commonly used for oocytes cryopreservation in women with cancer. However, evidence to support their effectiveness is yet modest. This study aims to compare the quality of ovarian response between the ovary carrying the dominant follicle or the corpus luteum (active ovary) and the contralateral ovary (resting ovary). Women with a diagnosis of malignancy who underwent oocytes cryopreservation were reviewed. The main inclusion criterion was the presence of a unilateral dominant follicle or a unilateral corpus luteum on the first day of ovarian hyperstimulation. The primary outcome was the number of mature oocytes retrieved. Intra-patient comparisons between the two ovaries were made using the nonparametric Wilcoxon test for paired data. Forty-three women were included. The number of mature oocytes retrieved from the active and the resting ovaries did not differ, the median [interquartile range-IQR] being 4 [2-7] and 5 [2-8], respectively (p = 0.09). The rate [IQR] of mature oocytes per developed follicle was 58% [40-80%] and 65% [33-87%], respectively (p = 0.42). In addition, no significant difference emerged when repeating the analyses separately for women carrying dominant follicles and for those carrying corpora lutea. This study failed to detect any detrimental effect of the presence of a dominant follicle or a corpus luteus on the ovarian response to hyperstimulation, thus supporting the validity of random start protocols.

The role of microbiota in female fertility and infertility.

In recent years, the introduction of advanced technologies has led to a new scientific revolution: the discovery of the human microbiota. Next-generation sequencing allowed the identification of microbial communities in all districts of the human body and, among these, 9% are distributed in the genitourinary system. The microbiota plays a key role in controlling the homeostasis, therefore dysbiosis can lead to an alteration of the physiological state of health. An alteration of female reproductive microbial communities may affect fertility due to an alteration of the vaginal and endometrial ecosystem. A perturbation of the vaginal, cervical or endometrial flora may also have an impact on the outcome of assisted reproductive technology procedures, particularly in vitro fertilization and embryo transfer. This review examines the role of microbiota in human reproduction and its contribution to infertility. In addition we investigate the role of endometrial bacteria in recurrent implantation failure.