Influence of Endometriosis on Assisted Reproductive Technology Outcomes: A Systematic Review and Meta-analysis

Evidence based management of patients with endometriosis undergoing assisted conception: British fertility society policy and practice recommendations

Endometriosis is a chronic inflammatory condition in women of reproductive age, which can lead to infertility and pelvic pain. Endometriosis associated infertility is multifactorial in nature adversely affecting each step of the natural reproductive physiology and thereby processes and outcomes of Assisted Reproductive Technology (ART) cycles. These outcomes are further complicated by the subtype of endometriosis, being peritoneal, deep infiltrating and ovarian, which bear negative effects on ovarian reserve, response to stimulation, accessibility for oocyte retrieval, intraoperative safety and endometrial receptivity. There is still a lack of clear guidance about the role of surgery for ovarian endometriosis/endometriomas. This guideline evaluates the evidence of the impact of pelvic endometriosis and endometriomas on the outcome of ART and provides recommendations for management options before and during ART including intra-uterine insemination. Recommendations are made based on the current evidence for the management of patients with endometriosis across each step of ART with the primary aim of improving ART outcomes.

The prevalence of endometriosis in unexplained infertility: a systematic review

In 15-30% of couples with infertility, no abnormalities are found after the initial diagnostic work-up. The aim of this study was to investigate the prevalence of endometriosis in patients with unexplained infertility undergoing diagnostic laparoscopy in the current era of improved imaging and assisted reproductive technology. A systematic search of PubMed, Embase and Cochrane Central was conducted to identify all studies reporting on pelvic pathologies found by laparoscopy in couples diagnosed with unexplained infertility. Normal ovulatory cycles, normal semen analysis and an infertility period of ≥12 months were the minimum requirements for a study population to be included. The prevalence of endometriosis was 44%, and most lesions were classified as minimal or mild (74%). The prevalence rates of tubal factors and adhesions were 20% and 16%, respectively. The detection rate for pelvic abnormalities was higher in women with prior fertility treatment (75%) compared with women without prior fertility treatment (53%). Despite the significant improvements in imaging for the diagnosis of endometriosis and tubal factors over the last decades, the prevalence rates of endometriosis and tubal abnormalities remain high in patients with unexplained infertility. The high prevalence of endometriosis in this population is important for decision-making in patients who also suffer from pain symptoms suggestive of endometriosis.

The Impact of Laparoscopic Surgery on Fertility Outcomes in Patients with Minimal/Mild Endometriosis

Minimal/mild endometriosis (MME) is independently associated with reduced fecundity rates. In this review article, we discuss the role of laparoscopic surgery in enhancing the fertility outcomes of patients with MME. Laparoscopic management of MME enhances fecundity and increases the chances of spontaneous conception in appropriately selected cases. However, laparoscopy cannot be routinely recommended in asymptomatic patients with the sole purpose of diagnosing and treating potentially present MME. Equally, and based on existing information, the laparoscopic management of MME cannot be routinely recommended prior to in vitro fertilisation (IVF) attempts due to the lack of robust and beneficial evidence. Because an overlap between unexplained infertility and MME cases likely exists, the development of reliable, widely available, non-invasive tests for the diagnosis of MME may revolutionise the management of cases currently classified as unexplained infertility. In a disease as diverse as endometriosis, management decisions should be based on a multitude of factors. Future studies should focus on reporting the outcomes of interventions for MME on fertility and obstetric outcomes, clearly differentiating between disease stages and phenotypes.

Australasian recurrent pregnancy loss clinical management guideline 2024, part II

Part II of the Australasian guideline for the investigation and management of recurrent pregnancy loss (RPL) provides evidence-based guidance on the management of RPL provided. The implications of inherited and acquired thrombophilia with respect to RPL and suggestions for clinical management are provided. Autoimmune factors, including human leukocyte antigen, cytokines, antinuclear antibodies and coeliac antibodies, and guidance for management are discussed. Infective, inflammatory and endometrial causes of RPL are discussed in detail. Environmental and lifestyle factors, male factor and unexplained causes are outlined. Levels of evidence and grades of consensus are provided for all evidence-based statements.

Endometriosis diagnosed by ultrasound is associated with lower live birth rates in women undergoing their first in vitro fertilization/intracytoplasmic sperm injection treatment

OBJECTIVE

To study the cumulative live birth rate (CLBR) after the first in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment in women with or without deep-infiltrating endometriosis (DIE) and/or endometrioma diagnosed by transvaginal ultrasonography (TVUS), using the International Deep Endometriosis Analysis (IDEA) group definitions.

DESIGN

Prospective observational cohort study at a university hospital.

PATIENTS(S)

In total, 1,040 women with subfertility aged 25 to ≤39 years were undergoing their first IVF/ICSI treatment between January 2019 and October 2022. Of these, 234 (22.5%; 95% confidence interval [CI], 20.0-25.0) women were diagnosed with DIE and/or endometrioma at systematic TVUS before starting their treatment.

INTERVENTION(S)

All women underwent their first IVF or ICSI treatment. Fresh and/or frozen embryos from the first cycle were used until pregnancy was achieved or no embryos remained.

MAIN OUTCOME MEASURE(S)

Cumulative live birth rate after the first IVF/ICSI cycle in women with or without DIE and/or endometrioma.

RESULT(S)

The CLBR after the first IVF/ICSI treatment in the total cohort of women was 426/1,040 (41.0%; 95% CI, 38.0-44.0). Women with DIE and/or endometrioma had a lower CLBR (78/234, 33.3%; 95% CI, 27.3-39.4) than women without the disease (348/806, 43.2%; 95% CI, 39.8-46.6). The crude relative risk (RR) for cumulative live birth for women with DIE and/or endometrioma was 0.77; 95% CI, 0.63-0.94, and after adjustments were made for age, body mass index, s-antimüllerian hormone, stimulation protocol, and day for embryo transfer, the adjusted RR was 0.63; 95% CI, 0.48-0.82. There was no difference in the number of retrieved mature oocytes, fertilization rate, or good quality embryos between the 2 groups.

CONCLUSION

The presence of DIE and/or endometrioma diagnosed by TVUS lowers the chance of live birth in women undergoing their first IVF/ICSI treatment.

The Effects of Long-Term Dienogest Therapy on In Vitro Fertilization Outcomes in Women with Endometriosis: A Systematic Review and Meta-Analysis

OBJECTIVES

Assessing dienogest's efficacy in endometriosis patients undergoing in vitro fertilization (IVF).

DATA SOURCES

Systematic search in databases (PubMed, MEDLINE, Embase, Web of Science, Cochrane CENTRAL, Google Scholar) until 1 October 2022.

STUDY SELECTIONS

Randomized trials and observational studies comparing extended dienogest pre-treatment, no pre-treatment, or gonadotropin-releasing hormone (GnRH) agonist pre-treatment in endometriosis-linked IVF.

OUTCOME MEASURES

live birth, clinical pregnancy rates, oocytes collected, miscarriage rate, gonadotropin consumption.

DATA EXTRACTIONS AND SYNTHESES

Two authors independently assessed eligibility. Dichotomous variables were analyzed via a random-effect model and Mantel-Haenszel method to calculate weighted estimates and 95% confidence intervals (CI). I2 statistic gauged study heterogeneity; GRADE criteria evaluated evidence quality.

CONCLUSIONS

Out of 191 publications, five studies with 723 participants were included. Uncertainty persists on whether prolonged dienogest affects live birth (RR 1.42, 95% CI 0.29 to 6.84; 3 studies, n = 289; I2 86%) and clinical pregnancy rates (RR 1.33, 95% CI 0.31 to 5.65; 3 studies, n = 289; I2 86%) compared to conventional IVF. Moreover, uncertainty remains regarding intervention impact on live birth (RR 1.46, 95% CI 0.63 to 3.37; 1 study, n = 34) and clinical pregnancy rates (RR 1.32, 95% CI 0.78 to 2.23; 3 studies, n = 288; I2 0%) versus long-term GnRH agonist therapy before IVF. Given limited data and very low evidence quality, doubts arise about the benefits of long-term dienogest pre-treatment before conventional IVF in endometriosis patients.

Impact of endometriosis on the ovarian follicles

A significant body of evidence has supported a negative impact of endometriosis on ovarian follicles; however, the origin and relevance of this ovarian impairment in endometriosis is still a matter of debate. The ovarian damage can be caused by endometriosis itself or by surgeries aiming to remove endometriotic lesions. In this review, we summarized the existing knowledge on the mechanisms by which endometriosis can impact the ovarian follicles, from molecular to clinical points of view. From a molecular standpoint, the presence of endometriosis or its consequences can induce oxidative stress, inflammation, aberrant mitochondrial energy metabolism and inappropriate steroid production in granulosa cells, phenomena that may impair the quality of oocytes to variable degrees. These alterations may have clinical relevance on the accelerated exhaustion of the ovarian reserve, on the ovarian response to gonadotrophin stimulation in IVF cycles and on the competence of the oocytes. Critical points to be considered in current clinical practices related to fertility issues in endometriosis are discussed.

Ovarian Stimulation for In Vitro Fertilization and Reproductive Outcome after Surgical Treatment of Endometriosis Compared with Tubal Factor Infertility

Endometriosis is a common cause of infertility among reproductive-age women. A low ovarian reserve is associated with the presence of endometriotic cysts, and this is accentuated even more after surgery. Patients with a history of endometrioma are a special category of poor ovarian reserve requiring in vitro fertilization (IVF). The aim of this retrospective study was to evaluate the characteristics and outcome of ovarian stimulation and embryo transfer in women with a history of ovarian surgery for endometrioma compared with a control group with tubal factor infertility. A total of 146 patients had previous laparoscopic cystectomy for endometrioma (group A) and their IVF results were compared with 136 patients with documented tubal obstruction (group B). In both groups, the most frequently used ovarian stimulation protocol was the short antagonist in 84.24% versus 80.88%. The number of stimulation days was between 6 and 15 days in the two groups with a mean value of 12.76 days in group A and 9.47 days in group B. The clinical pregnancy rate was 26.77% in the endometrioma group and 39.68% in the tubal obstruction group. Patients with a history of endometrioma are less likely to conceive than those with tubal obstruction despite having similar ovarian reserve and stimulation results.

Chronic low-grade inflammation and ovarian dysfunction in women with polycystic ovarian syndrome, endometriosis, and aging

The ovarian microenvironment is critical for follicular development and oocyte maturation. Maternal conditions, including polycystic ovary syndrome (PCOS), endometriosis, and aging, may compromise the ovarian microenvironment, follicular development, and oocyte quality. Chronic low-grade inflammation can induce oxidative stress and tissue fibrosis in the ovary. In PCOS, endometriosis, and aging, pro-inflammatory cytokine levels are often elevated in follicular fluids. In women with obesity and PCOS, hyperandrogenemia and insulin resistance induce ovarian chronic low-grade inflammation, thereby disrupting follicular development by increasing oxidative stress. In endometriosis, ovarian endometrioma-derived iron overload can induce chronic inflammation and oxidative stress, leading to ovarian ferroptosis and fibrosis. In inflammatory aging (inflammaging), senescent cells may secrete senescence-associated secretory phenotype factors, causing chronic inflammation and oxidative stress in the ovary. Therefore, controlling chronic low-grade inflammation and fibrosis in the ovary would present a novel therapeutic strategy for improving the follicular microenvironment and minimizing ovarian dysfunction.

Endometriosis and IVF treatment outcomes: unpacking the process

Advanced endometriosis is associated with a reduction of IVF success. Surgical damage to the ovarian reserve following the excision of endometriomas has been claimed as a critical factor in the explanation of this detrimental effect. However, it is generally inferred that other mechanisms might also hamper IVF success in affected women. They include diminished responsiveness to ovarian stimulation, altered steroidogenesis, a decline in oocyte quality, reduced fertilization and embryo development, and impaired implantation. To navigate these limitations, we scrutinized available literature for studies specifically designed to address distinct phases of the IVF process. Utmost consideration was given to intra-patient ovarian response comparisons in women with unilateral endometriomas and to studies applying a meticulous matching to control confounders. The following observations have been drawn: 1) endometriosis has a negligible impact on ovarian response. A slight reduction in stimulation response can only be observed for endometriomas larger than 4 cm. Follicular steroidogenesis is unaffected; 2) oocyte quality is not hampered. Fertilization rates are similar, and intracytoplasmic sperm injection (ICSI) is not justified. Embryonic development is uncompromised, with no increase in aneuploidy rate; 3) endometrial receptivity is either unaffected or only slightly impacted. In conclusion, our study suggests that, aside from the well-known negative effect on ovarian reserve from excisional endometrioma surgeries, endometriosis does not significantly affect IVF outcomes.

Development and validation of a nomogram model for predicting clinical pregnancy in endometriosis patients undergoing fresh embryo transfer

PURPOSE

To construct and validate a nomogram model for predicting clinical pregnancy in individuals with endometriosis undergoing fersh embryo transfer (ET).

METHODS

A retrospective analysis was conducted on 1630 individuals with endometriosis who underwent in vitro fertilization (IVF) with fresh embryo transfer at the Reproductive Medicine Center of Fujian Maternity and Child Health Hospital from January 2018 to January 2022. The research population was sorted into two groups through random sampling, namely, the model group (n = 1141) and the validation group (n = 489), with a ratio of 7:3. Univariate analysis was utilized to determine the influencing factors for clinical pregnancy in the model group. The LASSO algorithm was utilized to select the optimal matching factors, which were then included in a multifactorial forward stepwise logistic regression to determine independent influencing factors and develop a nomogram. The discrimination, accuracy, and clinical efficacy of the prediction model were analyzed utilizing the receiver operating characteristic (ROC) curve, calibration curve, and clinical decision curve.

RESULTS

Through multivariate-logistic-regression analysis, these factors were identified as independent influencing factors for the clinical pregnancy in endometriosis patients undergoing fresh embryo transfer: female age (OR = 0.933, 95% CI = 0.902-0.965, P < 0.001), ASRM stage (OR = 0.384, 95% CI = 0.276-0.532, P < 0.001), postoperative to IVF duration (OR = 0.496, 95% CI = 0.356-0.688, P < 0.001), antral follicle count (AFC) (OR = 1.076, 95% CI = 1.013-1.161, P = 0.045), anti-Müllerian hormone (AMH) (OR = 1.202, 95% CI = 1.073-1.35, P = 0.002), Gonadotrophin-releasing hormone (GnRH) agonist protocol (OR = 1.536, 95% CI = 1.109-2.131, P = 0.01), number of oocytes retrieved (OR = 1.154, 95% CI = 1.067-1.249, P < 0.001), number of high-quality cleavage embryos (OR = 1.261, 95% CI = 1.164-1.369, P < 0.001), and number of embryos transferred (OR = 1.957, 95% CI = 1.435-2.679, P < 0.001). A prediction model for estimating the clinical pregnancy probability in individuals with endometriosis was constructed per these identified independent factors. The ROC showed an area under the curve (AUC) of 0.807 (95% CI = 0.782-0.832) in the model group and 0.800 (95% CI = 0.761-0.84) in the validation group. The Hosmer-Lemeshow test demonstrated no statistically significant difference between predicted and actual clinical pregnancy probabilities (P > 0.05). The clinical decision curve demonstrated that both the model and the validation groups achieved maximum net benefit at threshold probability values of 0.08-0.96 and 0.16-0.96, indicating good clinical efficacy within this range of threshold probabilities.

CONCLUSION

Female age, ASRM stage, postoperative to IVF duration, stimulation protocol, AFC, AMH, number of oocytes retrieved, number of high-quality cleavage embryos and number of transferred embryos are independent influencing factors for the clinical pregnancy rate in individuals with endometriosis receiving fresh embryo transfer. The nomogram model based on these factors demonstrates good clinical predictive value and efficacy, providing a basis for clinical prognosis, intervention, and individualized medical treatment planning.

Exploring the Impact of Endometrioma Aspiration and Dienogest Combination Therapy on Cyst Size, Inflammatory Cytokines in Follicular Fluid and Fertility Outcomes

Endometriomas (chocolate cysts) are cystic lesions that can develop on ovaries, and are characterized by the presence of ectopic endometrial tissue or similar tissue. Such lesions can cause a decline in the number and quality of oocytes, and lead to implantation failure. In this study, we retrospectively assessed the efficacy of repeated endometrioma aspiration and dienogest combination therapy in patients suffering endometriosis-associated infertility with endometriomas. A comparison was made between a treated group that underwent combination therapy followed by controlled ovarian hyperstimulation (COH) (n = 30) and a control group that did not undergo treatment (n = 40), at the IVF Osaka Clinic from September 2019 to September 2021. There were no differences in patient background between the two groups. A reduction in endometrioma size continued for 12 months after treatment. The numbers of follicles that developed to 15 mm or greater in size following COH and mature oocytes were significantly lower in the treated group compared to those in the control group. The levels of inflammatory cytokines in the follicular fluid significantly decreased in the treated group (p < 0.05). In patients in the treated group who underwent a second ova retrieval, the results were compared between those in the first ova retrieval (immediately after the end of treatment) and those in the second ova retrieval (four months after the first retrieval). The numbers of follicles following COH, retrieved, mature and fertilized ova were significantly increased in the second ova retrieval.

Fertility Preservation in Women with Endometriosis

Several mechanisms have been implicated in the pathogenesis of endometriosis-related infertility. For patients considering surgery, the risk of iatrogenic injury is among the most important factors in the context of fertility preservation, along with age and individual reproductive goals. In the case of endometrioma excision, evidence overwhelmingly demonstrates the negative impact of surgery on ovarian reserve, with significant reductions in antimullerian hormone (up to 30% in unilateral versus up to 44% in bilateral endometriomas). The surgical endometriosis patient should be thoroughly counseled regarding fertility preservation and discussion should include tissue, embryo, and oocyte cryopreservation options. For the latter, data support cryopreservation of 10-15 oocytes in women ≤35 years and over 20 for those >35 years for a realistic chance to achieve one or more live births. When performing surgical interventions for endometriosis, reproductive surgeons should employ fertility-conserving surgical methods to reduce the likelihood of postoperative iatrogenic diminished ovarian reserve.

Oviductal extracellular vesicles from women with endometriosis impair embryo development

Objective

To investigate the influence of oviductal extracellular vesicles from patients with endometriosis on early embryo development.

Design

In vitro experimental study.

Setting

University-affiliated hospital.

Patients

Women with and without endometriosis who underwent hysterectomy (n = 27 in total).

Interventions

None.

Main outcome measures

Oviductal extracellular vesicles from patients with endometriosis (oEV-EMT) or without endometriosis (oEV-ctrl) were isolated and co-cultured with two-cell murine embryos for 75 hours. Blastocyst rates were recorded. RNA sequencing was used to identify the differentially expressed genes in blastocysts cultured either with oEV-EMT or with oEV-ctrl. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to identify potential biological processes in embryos that oEV-EMT affects. The functions of oEV on early embryo development were determined by reactive oxygen species (ROS) levels, mitochondrial membrane potentials (MMP), total cell numbers, and apoptotic cell proportions.

Results

Extracellular vesicles were successfully isolated from human Fallopian tubal fluid, and their characterizations were described. The blastocyst rates were significantly decreased in the oEV-EMT group. RNA sequencing revealed that oxidative phosphorylation was down-regulated in blastocysts cultured with oEV-EMT. Analysis of oxidative stress and apoptosis at the blastocysts stage showed that embryos cultured with oEV-EMT had increased ROS levels, decreased MMP, and increased apoptotic index. Total cell numbers were not influenced.

Conclusion

Oviductal extracellular vesicles from patients with endometriosis negatively influence early embryo development by down-regulating oxidative phosphorylation.

The Clinical Picture and Fecundity of Primary and Recurrent Ovarian Endometriosis with Family History: A Retrospective Analysis

This study aims to evaluate the role of endometriosis family history on the clinical manifestation and fertility performance of primary and recurrent endometriosis. In total, 312 primary and 323 recurrent endometrioma patients with a histological diagnosis were included in this study. Family history was significantly correlated with recurrent endometriosis (adjusted OR: 3.52, 95% CI: 1.09-9.46, p = 0.008). Patients with a family history showed a significantly higher proportion of recurrent endometriosis (75.76% vs. 49.50%), higher rASRM scores, higher incidence of severe dysmenorrhea, and severe pelvic pain than the sporadic cases. Recurrent endometrioma showed statistical increase in rASRM scores, percentage of rASRM Stage IV, dysmenorrhea, dyschezia, those undergoing semi-radical surgery or unilateral oophorosalpingectomy, postoperative medical treatment, e with a positive family history, while a decrease in the incidence of asymptomatic phenomena and those undergoing ovarian cystectomy compared to those with primary endometriosis. The naturally conceived pregnancy rate was higher in primary endometriosis compared to recurrent endometriosis. Compared to recurrent endometriosis with a negative family history, recurrent endometriosis with a positive family history had a higher incidence of severe dysmenorrhea, chronic pelvic pain, a higher spontaneous abortion rate, and a lower natural pregnancy rate. Primary endometriosis with a family history presented a higher incidence of severe dysmenorrhea than those without a family history. In conclusion, endometriosis patients with a positive family history presented a higher pain severity and lower conception probability compared to the sporadic cases. Recurrent endometriosis showed further-exacerbated clinical manifestations, more pronounced familial tendency, and lower pregnancy rates than primary endometriosis.

Endometriosis patients benefit from high serum progesterone in hormone replacement therapy-frozen embryo transfer cycles: a cohort study

RESEARCH QUESTION

What is the optimal serum progesterone cut-off level in patients with endometriosis undergoing hormone replacement therapy frozen embryo transfer (HRT-FET) with intensive progesterone luteal phase support?

DESIGN

A cohort study, including 262 HRT-FET cycles in 179 patients all diagnosed with endometriosis either by laparoscopy or by ultrasound in patients with visible endometriomas. Pre-treatment consisted of 42 days of oral contraceptive pills and 5 days' wash-out, followed by 6 mg oral oestrogen daily. Exogenous progesterone supplementation with vaginal progesterone gel 90 mg/12h commenced when the endometrium was 7 mm or thicker. From the fourth day of vaginal progesterone supplementation, patients also received intramuscular progesterone 50 mg daily. Blastocyst transfer was scheduled for the sixth day of progesterone supplementation.

RESULTS

The overall positive HCG, live birth (LBR) and total pregnancy loss rates were 60%, 39% and 34%, respectively. The optimal progesterone cut-off level was 118 nmol/l (37.1 ng/ml) defined as the maximum of the Youden index. The unadjusted LBR was significantly higher in patients with progesterone measuring 118 nmol/l or above compared with patients with progesterone measuring less than 118 nmol/l (51% [44/86] versus 34% [59/176], P = 0.01), whereas the adjusted odds ratio for a live birth was 2.1 (95% CI 1.2 to 3.7) after adjusting for age, body mass index, blastocyst score, blastocyst age, quality and number of blastocysts transferred.

CONCLUSIONS

Serum progesterone levels above 118 nmol/l (37.1ng/ml) resulted in significantly higher LBR compared with lower serum progesterone levels, suggesting that a threshold for optimal serum progesterone exists.

Higher miscarriage rate in subfertile women with endometriosis receiving unbiopsied frozen-warmed single blastocyst transfers

Background: Assisted reproductive technology treatment is recommended to overcome endometriosis-associated infertility but current evidence is controversial. Endometriosis is associated with lower antral follicle count (AFC) and oocyte yield but similar clinical outcomes compared to controls. Unaffected ovarian stimulation response and embryological outcomes but lower clinical pregnancy and live birth rates and higher miscarriage rates have been reported, implying direct impact on endometrial receptivity. With evidence emerging on the benefit of frozen-warmed and blastocyst stage transfer, we investigated ART outcomes in endometriosis using homogeneous case-control groups. Methods: This is a retrospective observational case-control study including n = 66 frozen-warmed unbiopsied single blastocyst transfers of patients with endometriosis and n = 96 of women exhibiting idiopathic sterility. All frozen-warmed transfers followed artificial endometrial preparation. Results: In control women, the mean number of oocytes recovered at oocyte pick up was higher compared to women with endometriosis (15.3 ± 7.1 vs. 12.7 ± 5.2, p = 0.025) but oocyte maturation index (mature oocytes/total oocytes at oocyte pick up) was significantly higher for endometriosis (48.2% vs. 34.0%, p = 0.005). The same was shown for the subgroup of 44 endometriosis patients after endometrioma surgery when compared with controls (49.1% vs. 34.0%, p = 0.014). Clinical pregnancy rate was not higher in endometriosis but was close to significance (47.0% vs. 32.3%, p = 0.059) while live birth rate was comparable (27.3% vs. 32.3%, p = 0.746). Miscarriage rate was higher in the endometriosis group (19.7% vs. 7.3%, p = 0.018). A significantly higher AFC was observed in the control group in comparison with the endometriosis group (16.3 ± 7.6 vs. 13.4 ± 7.0, p = 0.014). Live birth rate did not differ when comparing all endometriosis cases (p = 0.746), ASRM Stage I/II and Stage III/IV (p = 0.348 and p = 0.888) with the control group but the overall pregnancy rate was higher in ASRM Stage I/II (p = 0.034) and miscarriage rate was higher in ASRM Stage III/IV (p = 0.030) versus control. Conclusion: Blastocyst transfers in women with endometriosis originate from cycles with lower AFC but higher share of mature oocytes than in control women, suggesting that endometriosis might impair ovarian reserve but not stimulation response. A higher miscarriage rate, independent of blastocyst quality may be attributed to an impact of endometriosis on the endometrium beyond the timing of implantation.

Fertility preservation in women with benign gynaecological conditions

Although a wealth of data has been published regarding fertility preservation (FP) in women with malignant diseases who receive gonadotoxic treatment, the role of FP in non-malignant conditions has been studied to a much lesser extent. These include benign haematological, autoimmune, and genetic disorders, as well as a multitude of benign gynaecological conditions (BGCs) that may compromise ovarian reserve and/or reproductive potential due to pathogenic mechanisms or as a result of medical or surgical treatments. Alongside accumulating data that document the reproductive potential of cryopreserved oocytes and ovarian tissue, there is potential interest in FP for women with BGCs at risk of infertility; however, there are currently insufficient data about FP in women with BGCs to develop guidelines for clinical practice. The purpose of this article is to appraise the available evidence regarding FP for BGC and discuss potential strategies for FP based on estimated ovarian impairment and on short-term and long-term reproductive goals of patients. Cost-effectiveness considerations and patients' perspectives will also be discussed.

Pathophysiology, diagnosis, and management of endometriosis

Endometriosis affects approximately 190 million women and people assigned female at birth worldwide. It is a chronic, inflammatory, gynecologic disease marked by the presence of endometrial-like tissue outside the uterus, which in many patients is associated with debilitating painful symptoms. Patients with endometriosis are also at greater risk of infertility, emergence of fatigue, multisite pain, and other comorbidities. Thus, endometriosis is best understood as a condition with variable presentation and effects at multiple life stages. A long diagnostic delay after symptom onset is common, and persistence and recurrence of symptoms despite treatment is common. This review discusses the potential genetic, hormonal, and immunologic factors that lead to endometriosis, with a focus on current diagnostic and management strategies for gynecologists, general practitioners, and clinicians specializing in conditions for which patients with endometriosis are at higher risk. It examines evidence supporting the different surgical, pharmacologic, and non-pharmacologic approaches to treating patients with endometriosis and presents an easy to adopt step-by-step management strategy. As endometriosis is a multisystem disease, patients with the condition should ideally be offered a personalized, multimodal, interdisciplinary treatment approach. A priority for future discovery is determining clinically informative sub-classifications of endometriosis that predict prognosis and enhance treatment prioritization.

Endometriosis-associated infertility: From pathophysiology to tailored treatment

Despite the clinically recognized association between endometriosis and infertility, the mechanisms implicated in endometriosis-associated infertility are not fully understood. Endometriosis is a multifactorial and systemic disease that has pleiotropic direct and indirect effects on reproduction. A complex interaction between endometriosis subtype, pain, inflammation, altered pelvic anatomy, adhesions, disrupted ovarian reserve/function, and compromised endometrial receptivity as well as systemic effects of the disease define endometriosis-associated infertility. The population of infertile women with endometriosis is heterogeneous, and diverse patients' phenotypes can be observed in the clinical setting, thus making difficult to establish a precise diagnosis and a single mechanism of endometriosis related infertility. Moreover, clinical management of infertility associated with endometriosis can be challenging due to this heterogeneity. Innovative non-invasive diagnostic tools are on the horizon that may allow us to target the specific dysfunctional alteration in the reproduction process. Currently the treatment should be individualized according to the clinical situation and to the suspected level of impairment. Here we review the etiology of endometriosis related infertility as well as current treatment options, including the roles of surgery and assisted reproductive technologies.

The Impact of Controlled Ovarian Stimulation on Serum Oxidative Stress Markers in Infertile Women with Endometriosis Undergoing ICSI

Endometriosis-related infertility is associated with oxidative stress (OS). The present study aims to compare serum OS markers of infertile women with endometriosis and controls during the follicular phase of the natural cycle (D1), after pituitary downregulation using a GnRH agonist (D2), after controlled ovarian stimulation (COS) on the day of human chorionic gonadotropin administration (D3), and on the day of oocyte retrieval (D4). One hundred and eight serum samples (58 controls and 35 early and 18 advanced endometriosis cases) were collected at these four timepoints. OS markers were compared among the groups and timepoints using a linear regression model with mixed effects and a post-test using orthogonal contrasts. The significance was set at 5%. We observed altered OS markers in the endometriosis patients during the D1, D2, D3, and D4 timepoints compared to the controls. The evidence of systemic OS in infertile patients with endometriosis during COS suggests the mobilization of potent antioxidants in an attempt to protect the oocyte from oxidative damage, especially on the day of oocyte retrieval.

ESHRE guideline: endometriosis

STUDY QUESTION

How should endometriosis be diagnosed and managed based on the best available evidence from published literature?

SUMMARY ANSWER

The current guideline provides 109 recommendations on diagnosis, treatments for pain and infertility, management of disease recurrence, asymptomatic or extrapelvic disease, endometriosis in adolescents and postmenopausal women, prevention and the association with cancer.

WHAT IS KNOWN ALREADY

Endometriosis is a chronic condition with a plethora of presentations in terms of not only the occurrence of lesions, but also the presence of signs and symptoms. The most important symptoms include pain and infertility.

STUDY DESIGN SIZE DURATION

The guideline was developed according to the structured methodology for development of ESHRE guidelines. After formulation of key questions by a group of experts, literature searches and assessments were performed. Papers published up to 1 December 2020 and written in English were included in the literature review.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on the collected evidence, recommendations were formulated and discussed within specialist subgroups and then presented to the core guideline development group (GDG) until consensus was reached. A stakeholder review was organized after finalization of the draft. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help clinicians to apply best care for women with endometriosis. Although studies mostly focus on women of reproductive age, the guideline also addresses endometriosis in adolescents and postmenopausal women. The guideline outlines the diagnostic process for endometriosis, which challenges laparoscopy and histology as gold standard diagnostic tests. The options for treatment of endometriosis-associated pain symptoms include analgesics, medical treatments and surgery. Non-pharmacological treatments are also discussed. For management of endometriosis-associated infertility, surgical treatment and/or medically assisted reproduction are feasible. While most of the more recent studies confirm previous ESHRE recommendations, there are five topics in which significant changes to recommendations were required and changes in clinical practice are to be expected.

LIMITATIONS REASONS FOR CAUTION

The guideline describes different management options but, based on existing evidence, no firm recommendations could be formulated on the most appropriate treatments. Also, for specific clinical issues, such as asymptomatic endometriosis or extrapelvic endometriosis, the evidence is too scarce to make evidence-based recommendations.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in endometriosis care, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in endometriosis.

STUDY FUNDING/COMPETING INTERESTS

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive payments. C.M.B. reports grants from Bayer Healthcare and the European Commission; Participation on a Data Safety Monitoring Board or Advisory Board with ObsEva (Data Safety Monitoring Group) and Myovant (Scientific Advisory Group). A.B. reports grants from FEMaLE executive board member and European Commission Horizon 2020 grant; consulting fees from Ethicon Endo Surgery, Medtronic; honoraria for lectures from Ethicon; and support for meeting attendance from Gedeon Richter; A.H. reports grants from MRC, NIHR, CSO, Roche Diagnostics, Astra Zeneca, Ferring; Consulting fees from Roche Diagnostics, Nordic Pharma, Chugai and Benevolent Al Bio Limited all paid to the institution; a pending patent on Serum endometriosis biomarker; he is also Chair of TSC for STOP-OHSS and CERM trials. O.H. reports consulting fees and speaker's fees from Gedeon Richter and Bayer AG; support for attending meetings from Gedeon-Richter, and leadership roles at the Finnish Society for Obstetrics and Gynecology and the Nordic federation of the societies of obstetrics and gynecology. L.K. reports consulting fees from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; honoraria for lectures from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; support for attending meetings from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; he also has a leadership role in the German Society of Gynecological Endocrinology (DGGEF). M.K. reports grants from French Foundation for Medical Research (FRM), Australian Ministry of Health, Medical Research Future Fund and French National Cancer Institute; support for meeting attendance from European Society for Gynaecological Endoscopy (ESGE), European Congress on Endometriosis (EEC) and ESHRE; She is an advisory Board Member, FEMaLe Project (Finding Endometriosis Using Machine Learning), Scientific Committee Chair for the French Foundation for Research on Endometriosis and Scientific Committee Chair for the ComPaRe-Endometriosis cohort. A.N. reports grants from Merck SA and Ferring; speaker fees from Merck SA and Ferring; support for meeting attendance from Merck SA; Participation on a Data Safety Monitoring Board or Advisory Board with Nordic Pharma and Merck SA; she also is a board member of medical advisory board, Endometriosis Society, the Netherlands (patients advocacy group) and an executive board member of the World Endometriosis Society. E.S. reports grants from National Institute for Health Research UK, Rosetrees Trust, Barts and the London Charity; Royalties from De Gruyter (book editor); consulting fees from Hologic; speakers fees from Hologic, Johnson & Johnson, Medtronic, Intuitive, Olympus and Karl Storz; Participation in the Medicines for Women's Health Expert Advisory Group with Medicines and Healthcare Products Regulatory Agency (MHRA); he is also Ambassador for the World Endometriosis Society. C.T. reports grants from Merck SA; Consulting fees from Gedeon Richter, Nordic Pharma and Merck SA; speaker fees from Merck SA, all paid to the institution; and support for meeting attendance from Ferring, Gedeon Richter and Merck SA. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgement to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose (Full disclaimer available at www.eshre.eu/guidelines.).

Delayed diagnosis of endometriosis disadvantages women in ART: a retrospective population linked data study

STUDY QUESTION

Do the outcomes and use of ART differ between women with and without endometriosis?

SUMMARY ANSWER

ART use and outcome do not appear to differ for women with and without endometriosis, as long as endometriosis is diagnosed prior to commencing ART.

WHAT IS KNOWN ALREADY

Approximately 40% of women with endometriosis have infertility and ART is the recommended treatment option for these women. However, diagnosis of endometriosis can be complex and lengthy, and a delay in diagnosis can reduce the likelihood of achieving a live birth.

STUDY DESIGN, SIZE, DURATION

This retrospective national cohort study used longitudinal self-report data (collected 1996-2018) from women born in 1973-1978 who are participants in the Australian Longitudinal Study on Women's Health (ALSWH). The study also used linked administrative data on Endometriosis (1970-2018), ART (1996-2020) and births (1996-2018).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The outcome measures were: age at first ART cycle; use of ART treatments (IVF only; IUI only/and IVF); number of ART cycles (1-3; 4-10; 11-36); and births after first ART (no; yes) (note that births could not be tied to ART).

MAIN RESULTS AND THE ROLE OF CHANCE

One in three (34.7%, n = 459/1322) women using ART had endometriosis, with 65.6% of these diagnosed before first ART and 34.4% after. Adjusted regression analyses showed women with endometriosis diagnosed before first ART were not significantly different to women without endometriosis on any outcome. However, women with endometriosis diagnosed after first ART were more likely to use IUI (adjusted odds ratio (aOR) 2.14, 95% CI 1.48, 3.09) and do more cycles (11-36 cycles: aOR 4.09, 95% CI 2.41, 6.95), and less likely to report a birth (aOR 0.67, 95% CI 0.45, 0.99), compared to women without endometriosis, despite no significant difference in starting age (coefficient = -0.62, 95% CI -1.36, 0.13).

LIMITATIONS, REASONS FOR CAUTION

We did not have information on the severity of endometriosis, or the reasons for using ART, which can influence treatment and outcomes. We were not able to reliably link births with ART treatment. Finally, it is possible that some of the women in our 'no endometriosis' group did have endometriosis and were unaware of it, although prevalence rates match population estimates.

WIDER IMPLICATIONS OF THE FINDINGS

These findings support previous studies that have found no difference in outcome of ART for women with endometriosis, but add the new insight that this is only true if endometriosis is diagnosed prior to commencing ART. A delayed diagnosis can create disadvantage during ART treatment. Early recourse to IVF may be advantageous for pregnancy prospects for women with endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

The ALSWH is funded by the Australian Government Department of Health. G.D.M. is supported by an NHMRC Principal Research Fellowship (APP11218449). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Managing endometrioma to optimize future fertility

The management of endometriomas in women wishing to preserve their fertility is complex. While surgery can help to achieve pregnancy in some, it may also have a detrimental effect on a woman's ovarian reserve. The present article reviews the impact of endometriomas on fertility and the different management approaches that should be considered in women who wish to preserve their fertility. This study also reviews the role of assisted reproduction in the setting of endometriomas, and the evolving role of oocyte cryopreservation for this benign but progressive disease. Using evidence from the latest guidelines and major publications, we emphasize the need to consider the woman's future fertility when navigating the diverse range of management strategies available, and outline an evidence-based framework to help facilitate fertility-friendly discussion, counseling and management of this complex disease.

Conservative Management of Rectovaginal Deep Endometriosis: Shaving Should Be Considered as the Primary Surgical Approach in a High Majority of Cases

Deep endometriosis infiltrating the rectum remains a challenging situation to manage, and it is even more important when ureters and pelvic nerves are also infiltrated. Removal of deep rectovaginal endometriosis is mandatory in case of symptoms strongly impairing quality of life, alteration of digestive, urinary, sexual and reproductive functions, or in case of growing. Extensive preoperative imaging is required to choose the right technique between laparoscopic shaving, disc excision, or rectal resection. When performed by skilled surgeons and well-trained teams, a very high majority of cases of deep endometriosis nodule (>95%) is feasible by the shaving technique, and this is associated with lower complication rates regarding rectal resection. In most cases, removing a part of the rectum is questionable according to the risk of complications, and the rectum should be preserved as far as possible. Shaving and rectal resection are comparable in terms of recurrence rates. As shaving is manageable whatever the size of the lesions, surgeons should consider rectal shaving as first-line surgery to remove rectal deep endometriosis. Rectal stenosis of more than 80% of the lumen, multiple bowel deep endometriosis nodules, and stenotic sigmoid colon lesions should be considered as indication for rectal resection, but this represents a minority of cases.

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

BACKGROUND

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

OBJECTIVE AND RATIONALE

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

SEARCH METHODS

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

OUTCOMES

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

WIDER IMPLICATIONS

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

The ultra-long study: a randomized controlled trial evaluating long-term GnRH downregulation prior to ART in women with endometriosis

STUDY QUESTION

Does ultra-long downregulation with a GnRH agonist (triptorelin depot) in previously operated patients with endometriosis improve the rate of clinical pregnancy with positive fetal heart beat (CPHB) in the subsequent initiated fresh ART cycle?

SUMMARY ANSWER

Ultra-long downregulation with a GnRH agonist prior to ART did not improve the rate of CPHB in the subsequent fresh ART cycle in previously completely operated patients but the trial was underpowered due to early termination.

WHAT IS KNOWN ALREADY

Administration of GnRH agonists for a period of 3-6 months prior to ART in women with endometriosis may increase the odds of clinical pregnancy. However, the quality of the studies on which this statement is based is questionable, so these findings need confirmation.

STUDY DESIGN, SIZE, DURATION

A controlled, randomized, open label trial was performed between 1 June 2013 and 31 December 2016 (start and end of recruitment, respectively). Patients with prior complete laparoscopic treatment of any type or stage of endometriosis and an indication for ART were randomized (by a computer-generated allocation sequence) into two groups: the control group underwent ART stimulation in a classical long agonist protocol using preparation with oral contraceptives, the ultra-long group first underwent at least 3 months downregulation followed by a long agonist protocol for ART stimulation. The sample size was calculated to detect a superiority of the ultra-long downregulation protocol, based on the hypothesis that baseline CPHB rate in the control group of 20% would increase to 40% in the ultra-long group. For a power of 20% at a significance level of 5%, based on two-sided testing, including 5% of patients lost to follow-up, the necessary sample size was 172 patients (86 per group).

PARTICIPANTS/MATERIALS, SETTING, METHODS

This trial was conducted at the Leuven University Fertility Center, a tertiary care center for endometriosis and infertility, and a total of 42 patients were randomized (21 in the control group and 21 in the ultra-long group).

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline characteristics were similar in both groups. The primary outcome studied-CPHB after the initiated ART treatment-did not differ and was 25% (5/20) in the control group, and 20% (4/20) in the ultra-long group (P > 0.999; relative risk (RR) 1.25, 95% CI 0.41-3.88). Cumulative (fresh + associated frozen) CPHB rates were also similar in the control versus ultra-long group (8/20, 40% vs 6/20, 30%, P = 0.7411; RR = 1.33, 95% CI 0.57-3.19). When other secondary outcomes were compared with the ultra-long group, patients from the control group had a shorter duration of stimulation (mean 11.8 days (SD ± 2.4) versus 13.2 days (SD ± 1.5), P = 0.0373), a lower total dose of gonadotrophins used (mean 1793 IU/d (SD ± 787) vs 2329 (SD ± 680), P = 0.0154), and a higher serum estradiol concentration (ng/ml) at the end of ovarian stimulation on the day of ovulation triggering or cycle cancellation (mean1971 (SD ± 1495) vs 929 (± 548); P = 0.0326), suggesting a better ovarian response in the control group.

LIMITATIONS, REASONS FOR CAUTION

Due to a strong patient preference, nearly exclusively against ultra-long downregulation (even though patients were thoroughly informed of the potential benefits), the targeted sample size could not be achieved and the trial was stopped prematurely.

WIDER IMPLICATIONS OF THE FINDINGS

Conditional power analysis revealed that the probability of confirming the study hypothesis if the study were completed would be low. We hypothesize that in patients with prior complete surgical treatment of endometriosis, the ultra-long protocol does not enhance ART-CPHB rates. Patient's concerns and preferences regarding possible side-effects, and delay of ART treatment start with the ultra-long protocol should be taken into account when considering this type of treatment in women with endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

C.T. was during 2 years funded by a grant from the Clinical research Foundation of UZ Leuven (KOF) and during 2 years by the Research Foundation-Flanders (FWO grant number: 1700816N). C.T. reports grants from Clinical Research Foundation of the University Hospitals of Leuven (KOF), grants from Fund for Scientific Research Flanders (FWO), during the conduct of the study; grants, non-financial support and other from Merck SA, non-financial support and other from Gedeon Richter, non-financial support from Ferring Pharmaceuticals, outside the submitted work. T.D. is vice president and head of Global Medical Affairs Fertility, Research and Development, Merck KGaA, Darmstadt, Germany. He is also a professor in Reproductive Medicine and Biology at the Department of Development and Regeneration, Group Biomedical Sciences, KU Leuven (University of Leuven), Belgium and an adjunct professor at the Department of Obstetrics and Gynecology in the University of Yale, New Haven, USA. Neither his corporate role nor his academic roles represent a conflict of interest with respect to the work done by him for this study. A.C. reports personal fees from Merck S.p.A., outside the submitted work. The other co-authors have no conflict of interest.

TRIAL REGISTRATION NUMBER

UZ Leuven trial registry SS55300, EudraCT number 2013-000993-32, clinicaltrials.gov NCT02400801.

TRIAL REGISTRATION DATE

Registration for EudraCT on 1 March 2013.

DATE OF FIRST PATIENT’S ENROLMENT

4 September 2013.

Does Ovarian Endometriosis Increase Oocyte Sensitivity to ICSI-Induced Mechanical Damage?

Some studies have shown that ICSI obtains poorer results than conventional IVF in women with ovarian endometriosis, suggesting that oocytes could be sensitive to ICSI-induced mechanical damage. The aims of this study were to clarify (a) whether ovarian endometriosis could induce peculiar fragility in the oocyte, so that ICSI would finally result harmful, and (b) whether endometrioma removal before IVF could be advisable in order to avoid any hypothetical detrimental effect. We retrospectively studied 368 women, 203 with in situ endometrioma (128 of which underwent ICSI, 75 conventional IVF) and 164 who received laparoscopic stripping of endometrioma before ICSI. For women with in situ endometrioma, cIVF and ICSI outcome was comparable for all parameters studied, including the clinical pregnancy rate per embryo transfer (PR/ET: 31.8% vs. 39.5% in the cIVF and ICSI groups) and cumulative live birth rate per ovum pick-up (CLBR/OPU: 24.4% vs. 27.7%). ICSI outcome was similar comparing women with in situ endometrioma and women previously submitted to laparoscopic stripping of cysts (CLPR/OPU 27.7% vs. 25.3%). Our findings suggest that (a) in women with in situ endometrioma ICSI may be performed, when needed, without harming oocytes and compromising the outcome and (b) that there is no advantage in removing endometrioma before ICSI.

Melatonin and its mechanism of action in the female reproductive system and related malignancies

Melatonin (N-acetyl-5-methoxytryptamine), the main product of pineal gland in vertebrates, is well known for its multifunctional role which has great influences on the reproductive system. Recent studies documented that melatonin is a powerful free radical scavenger that affects the reproductive system function and female infertility by MT1 and MT2 receptors. Furthermore, cancer researches indicate the influence of melatonin on the modulation of tumor cell signaling pathways resulting in growth inhibitor of the both in vivo/in vitro models. Cancer adjuvant therapy can also benefit from melatonin through therapeutic impact and decreasing the side effects of radiation and chemotherapy. This article reviews the scientific evidence about the influence of melatonin and its mechanism of action on the fertility potential, physiological alteration, and anticancer efficacy, during experimental and clinical studies.

Assisted reproductive technology for women with endometriosis, a clinically oriented review

PURPOSE OF REVIEW

To discuss optimal management of an assisted reproductive technology (ART) cycle in women with endometriosis.

RECENT FINDINGS

New studies involving euploid embryo transfers provide more insight on the etiology of endometriosis-associated infertility. Oocyte competence to reach live birth seems unlikely to be affected by the disease. Routine medical or surgical treatment prior to an ART cycle does not appear beneficial. Short gonadotropin releasing hormone (GnRH) antagonist or progestin primed ovarian stimulation protocols seem to be proper first choices, depending on the intention for a fresh embryo transfer. Low-quality evidence supports frozen thawed over fresh embryo transfer. Ovarian stimulation for ART does not seem to be associated with symptom progression or recurrence.

SUMMARY

How endometriosis affects fertility is still unclear, but ART is an effective pragmatic treatment. Each woman with endometriosis must be assessed with a holistic approach, and in the absence of an indication for otherwise, ART cycles can be kept simple with patient-friendly protocols. Whether a frozen embryo transfer is better than a fresh one should be investigated.

Follicular Fluid from Infertile Women with Mild Endometriosis Impairs In Vitro Bovine Embryo Development: Potential Role of Oxidative Stress

OBJECTIVE

 To investigate whether follicular fluid (FF) from infertile women with mild endometriosis (ME) alters in vitro bovine embryo development, and whether the antioxidants N-acetyl-cysteine (NAC) and/or L-carnitine (LC) could prevent such damages.

METHODS

 Follicular fluid was obtained from infertile women (11 with ME and 11 control). Bovine oocytes were matured in vitro divided in: No-FF, with 1% of FF from control women (CFF) or ME women (MEFF); with 1.5 mM NAC (CFF + NAC, MEFF + NAC), with 0.6 mg/mL LC (CFF + LC, MEFF + LC), or both antioxidants (CFF + NAC + LC, MEFF + NAC + LC). After in vitro fertilization, in vitro embryo culture was performed for 9 days.

RESULTS

 A total of 883 presumptive zygotes were cultured in vitro. No differences were observed in cleavage rate (p = 0.5376) and blastocyst formation rate (p = 0.4249). However, the MEFF group (12.5%) had lower hatching rate than the No-FF (42.1%, p = 0.029) and CFF (42.9%, p = 0.036) groups. Addition of antioxidants in the group with CFF did not alter hatching rate (p ≥ 0.56), and in groups with MEFF, just NAC increased the hatching rate [(MEFF: 12.5% versus MEFF + NAC: 44.4% (p = 0.02); vs MEFF + LC: 18.8% (p = 0.79); versus MEFF + NAC + LC: 30.8% (p = 0.22)].

CONCLUSION

 Therefore, FF from infertile women with ME added to medium of in vitro maturation of bovine oocytes impairs hatching rate, and NAC prevented these damages, suggesting involvement of oxidative stress in worst of oocyte and embryo quality of women with ME.

Miscarriage on Endometriosis and Adenomyosis in Women by Assisted Reproductive Technology or with Spontaneous Conception: A Systematic Review and Meta-Analysis

Background

In the past several years, there has been an increasing concern on miscarriage caused by endometriosis or adenomyosis. However, the results reported by different studies remain controversial. The present study is aimed at assessing the impact of endometriosis and adenomyosis on miscarriage.

Materials and Methods

Searches were carried out in PubMed, Embase, and the Cochrane library for studies published from inception until February 29, 2020. The investigators included studies that evaluated miscarriage risk in pregnant women with endometriosis or adenomyosis by assisted reproductive technology (ART), or with spontaneous conception (SC). Miscarriage (<28 weeks) was the primary outcome. The secondary outcomes were antepartum hemorrhage (APH), postpartum hemorrhage (PPH), preterm birth, low birthweight, placenta praevia, placental abruption, ectopic pregnancy, stillbirth, gestational diabetes, preeclampsia, and intrauterine growth restriction (IUGR). Endnote was used for the study collection, and the data analyses were carried out by two authors using Review Manager version 5.2.

Results

Thirty-nine studies, which is comprised of 697,984 women, were included in the present study. Miscarriage risk increased in women with endometriosis in SC (OR: 1.81, 95% CI: 1.44-2.28, I² = 96%) compared with those without endometriosis, while women with endometriosis who underwent ART had a similar miscarriage risk, when compared to those with tubal infertility (OR: 1.03, 95% CI: 0.92-1.14, I² = 0%). Compared with those without adenomyosis, women with adenomyosis had an augmented miscarriage risk in ART (OR: 2.81, 95% CI: 1.44-5.47, I² = 64%). Compared with those without endometriosis, women with endometriosis had higher odds of APH, PPH, preterm birth, stillbirth, and placenta praevia. No difference was observed in the incidence of ectopic pregnancy, placental abruption, pre-eclampsia, gestational diabetes, low birthweight, and IUGR.

Conclusion

Women with endometriosis had an augmented miscarriage risk in SC and a similar miscarriage risk during ART. Adenomyosis was associated with miscarriage in pregnant women using ART.

The freeze-all strategy after IVF: which indications?

The freeze-all strategy is gaining popularity worldwide as an alternative to the conventional fresh embryo transfer. It consists of cryopreservation of the entire embryo cohort and the embryo transfer in a subsequent cycle that takes place separately from ovarian stimulation. The freeze-all strategy was initially a 'rescue' strategy for women at high risk of ovarian hyperstimulation syndrome; however, this approach has been extended to other indications as a scheduled strategy to improve implantation rates. This assumes that ovarian stimulation can alter endometrial receptivity in fresh cycles owing to the effect of supraphysiological levels of steroids on endometrial maturation. The procedure, however, has not been associated with increased live birth rates in all infertile couples, and concerns have been raised about the occurrence of several adverse perinatal outcomes. It is, therefore, crucial to identify in which subgroups of patients a freeze-all strategy could be beneficial. The aim of this review is to summarize current scientific research in this field to highlight potential indications for this strategy and to guide clinicians in their daily practice.

Obstetrical complications and outcome in patients with endometriosis

Endometriosis is a disease that has a profound impact on the quality of life of women, due to the associated chronic pelvic pain, dysmenorrhea, dyspareunia and infertility. However, even getting long-awaited pregnancy (often after assisted reproductive technologies), patients with endometriosis have a high risk of obstetric complications, such as miscarriage, preterm birth, preeclampsia, placental abnormalities, hemorrhage in labor, birth of small for gestational age infants, stillbirth and higher cesarean section rate. In addition, during pregnancy acute complications of endometriosis may occur, such as spontaneous hemoperitoneum, which is rare but life-threatening conditions that in most cases require surgical intervention. The mechanisms of the observed complications in pregnant women with endometriosis are not fully understood. This review presents literature data and personal considerations on the effect of endometriosis on pregnancy outcome and the occurrence of complications, as well as their possible underlined mechanisms. Based on this, we proposed ways to reduce the risk of obstetric complications in pregnant women with a history of endometriosis.

Deep endometriosis: The place of laparoscopic shaving

Deep endometriosis (DE) is considered to be one of the most challenging conditions to manage, especially when it invades surrounding organs like the rectum. Surgical excision of deep rectovaginal endometriosis is required when lesions are symptomatic, impairing bowel, urinary, sexual, and reproductive functions, or if they evolve. Preoperative radiological examination should be extensive to determine the appropriate surgery: laparoscopic shaving, disc excision, or rectal resection. We demonstrated that in the hands of experienced surgeons, rectal shaving is possible for DE in more than 95% of cases, with low complication rates compared to rectal resection. Shaving and bowel resection are associated with comparable recurrence rates. As shaving is indicated whatever the size of deep lesions, surgeons should first consider rectal shaving to remove DE. Bowel resection should only be performed in case of major rectal stenosis (>80%), multiple and/or posterior rectal lesions and stenotic sigmoid colon lesions.

Endometrial stromal cell inflammatory phenotype during severe ovarian endometriosis as a cause of endometriosis-associated infertility

RESEARCH QUESTION

Do endometrial stromal cells from primary infertile patients with severe ovarian endometriosis display differential secretory profiles of inflammation-associated cytokines during the implantation window that may cause infertility?

DESIGN

Forty-eight cytokines were measured in conditioned medium of isolated endometrial stromal cells obtained from primary infertile patients without endometriosis (control group, n = 12) or with stage IV ovarian endometriosis (ovarian endometriosis group, n = 14) using multiplex assays. Key cytokines showing differential secretory profiles were validated using Western immunoblotting. Cellular phenotypic validation was carried out in vitro by comparing proliferation and migration capacity between control (n = 6) and ovarian endometriosis (n = 7) groups.

RESULTS

CCL3, CCL4, CCL5, CXCL10, FGF2, IFNG, IL1RN, IL5, TNFA, and VEGF could be detected only in the conditioned media of stromal cells obtained from the ovarian endometriosis group. Among other cytokines detected in the conditioned media of both groups, CCL2 (P = 0.0018), CSF3 (P = 0.0017), IL1B (P = 0.0066), IL4 (P = 0.036), IL6 (P = 0.0039) and IL13 (P = 0.036) were found to be higher, whereas the concentration of IL18 was lower (P = 0.023) in the ovarian endometriosis group. Concentrations of CCL2, IL1B, IL4 and IL13 in conditioned medium reflected significant diagnostic performance for predicting ovarian endometriosis. Cellular phenotypic validation in vitro revealed an enhanced proliferative phenotype (P = 0.046) with no change in cell migratory capacity of endometrial stromal cells from the ovarian endometriosis group.

CONCLUSIONS

Endometrial stromal cells derived from severe ovarian endometriosis samples displayed a hyperinflammatory and hyperproliferative bias in the endometrial stroma during the 'window of implantation' putatively causing loss of fecundability.

Reproductive, obstetric, and perinatal outcomes of women with adenomyosis and endometriosis: a systematic review and meta-analysis

BACKGROUND

The reproductive impact of adenomyosis and endometriosis is widely researched but the extent of these impacts remains elusive. It has been demonstrated that endometriosis, in particular, is known to result in subfertility but endometriosis and adenomyosis are increasingly linked to late pregnancy complications such as those caused by placental insufficiency. At the molecular level, the presence of ectopic endometrium perturbs the endometrial hormonal, cellular, and immunological milieu, negatively influencing decidualization, placentation, and developmental programming of the embryo. It is unclear if and how such early aberrant reproductive development relates to pregnancy outcomes in endometriosis and adenomyosis.

OBJECTIVE AND RATIONALE

The aims of this systematic review and meta-analysis were to (i) investigate the association of adenomyosis and endometriosis with fertility, obstetric, and neonatal outcomes of women through both assisted reproduction and natural conception and (ii) determine whether endometriosis disease subtypes have specific impacts on different stages of the reproductive process.

SEARCH METHODS

A systematic literature review of NHS evidence electronic databases and the Cochrane database identified all comparative and observational studies between 1980 and December 2018 in any language on adenomyosis and endometriosis with fertility, obstetric, and neonatal outcomes (23 search terms used). A total of 104 papers were selected for data extraction and meta-analysis, with use of Downs and Black standardized checklist to evaluate quality and bias.

OUTCOMES

We found that endometriosis consistently leads to reduced oocyte yield and a reduced fertilization rate (FR), in line with current evidence. Milder forms of endometriosis were most likely to affect the fertilization (FR OR 0.77, CI 0.63-0.93) and earlier implantation processes (implantation rate OR 0.76, CI 0.62-0.93). The more severe disease by American Society for Reproductive Medicine staging (ASRM III and IV) influenced all stages of reproduction. Ovarian endometriosis negatively affects the oocyte yield (MD -1.22, CI -1.96, -0.49) and number of mature oocytes (MD -2.24, CI -3.4, -1.09). We found an increased risk of miscarriage in both adenomyosis and endometriosis (OR 3.40, CI 1.41-8.65 and OR 1.30, CI 1.25-1.35, respectively), and endometriosis can be associated with a range of obstetric and fetal complications including preterm delivery (OR 1.38, CI 1.01-1.89), caesarean section delivery (OR 1.98 CI 1.64-2.38), and neonatal unit admission following delivery (OR 1.29, CI 1.07-1.55).

WIDER IMPLICATIONS

Adenomyosis and the subtypes of endometriosis may have specific complication profiles though further evidence is needed to be able to draw conclusions. Several known pregnancy complications are likely to be associated with these conditions. The complications are possibly caused by dysfunctional uterine changes leading to implantation and placentation issues and therefore could potentially have far-reaching consequences as suggested by Barker's hypothesis. Our findings would suggest that women with these conditions should ideally receive pre-natal counselling and should be considered higher risk in pregnancy and at delivery, until evidence to the contrary is available. In order to expand our knowledge of these conditions and better advise on future management of these patients in reproductive and maternal medicine, a more unified approach to studying fertility and reproductive outcomes with longer term follow-up of the offspring and attention to the subtype of disease is necessary.

Oocyte vitrification for fertility preservation in women with endometriosis: an observational study

OBJECTIVE

To describe the outcome of fertility preservation (FP) using vitrified oocytes in patients with endometriosis and to determine the impact of ovarian surgery.

DESIGN

Retrospective observational study.

SETTING

University-affiliated private in vitro fertilization (IVF) center.

PATIENT(S)

Four hundred and eighty-five women with endometriosis who underwent FP from January 2007 to July 2018.

INTERVENTION(S)

Vitrification of metaphase II (MII) oocytes for future use.

MAIN OUTCOME MEASURE(S)

Oocyte survival rate and cumulative live-birth rate (CLBR).

RESULT(S)

Mean age at vitrification was 35.7 ± 3.7 years. The women undergoing operations were younger than the nonsurgical patients (33.4 ± 3.6 years vs. 36.7 ± 3.7 years). The survival rate and CLBR were 83.2% and 46.4%, respectively. The number of vitrified oocytes per cycle (6.2 ± 5.8) was higher for the nonsurgical patients compared with the unilateral (5.0 ± 4.5) or bilateral (4.5 ± 4.4) surgery groups, but was comparable among the surgical patients. The effect of age (adjusted odds ratio [OR] 0.904; 95% CI, 0.858-0.952), number of oocytes (adjusted OR 1.050; 95% CI, 1.025-1.091), and survival (adjusted OR 1.011; 95% CI, 1.001-1.020) on the CLBR was confirmed. However, the effect of surgery was not observed (adjusted OR 1.142; 95% CI, 0.778-1.677). Nonetheless, the ovarian response (vitrified oocytes = 8.6 ± 6.9 vs. 5.1 ± 4.8) and CLBR (72.5% vs. 52.8%) were higher in young (≤35 years) nonsurgical patient versus the surgical patients; older women showed similar outcomes.

CONCLUSION(S)

Fertility preservation gives patients with endometriosis a valid treatment option to help them increase their reproductive chances. We suggest performing surgery after ovarian stimulation for FP in young women. In older women, an individualized treatment should be considered.

Peripheral Estrogens in Women with Endometriosis Undergoing IVF

A consistent body of in vitro evidence supports a detrimental effect of endometriosis on ovarian steroidogenesis, in particular the synthesis of estrogens. However, clinical evidence is scanty and methodologically weak. This study aimed at clarifying whether peripheral 17-β-estradiol during IVF are influenced by the presence of endometriosis. Women undergoing IVF were retrospectively reviewed. Cases were women with a diagnosis of endometriosis. Controls were matched to cases in a 1:1 ratio by study period, age, total number of developed follicles on the day of hCG administration, protocol of hyperstimulation, gonadotropin used, and starting dose. The primary outcome was the ratio between serum levels of 17-β-estradiol and the total number of developed follicles. Fifty-three women with endometriosis and 53 controls were selected. The median ratio (interquartile range) between serum 17-β-estradiol and the total number of developed follicles in the two groups was 207 (164-282) and 201 (144-268) pg/ml, respectively (p = 0.46). Sensitivity analyses on the magnitude of the follicular response, the history of surgery for endometriomas, and the presence of endometriomas did not show any subgroup at increased risk of peripheral estrogens impairment. Endometriosis does not influence peripheral levels of 17-β-estradiol during IVF. Our findings argue against a biologically relevant effect of the disease on ovarian estrogen-synthesis.

Does Endometriosis Influence the Embryo Quality and/or Development? Insights from a Large Retrospective Matched Cohort Study

In vitro fertilization can be an effective tool to manage the endometriosis-associated infertility, which accounts for 10% of the strategy indications. Nevertheless, a negative effect of endometriosis on IVF outcomes has been suggested. The aim of this study was to evaluate the potential effect of endometriosis in the development of embryos at cleavege stage in assisted reproduction treatment cycles. A total of 429 cycles from women previously operated for moderate/severe endometriosis were compared with 851 cycles from non-affected women. Patients were matched by age, number of oocyte retrieved and study period. A total of 3818 embryos in cleavage stage have been analyzed retrospectively. Overall, no difference was found between women with and without endometriosis regarding the number of cleavage stage embryos obtained as well as the percentage of good/fair quality embryos. Excluding cycles in which no transfers were performed or where embryos were frozen in day three, no difference was observed for blastulation rate or the percentage of good/fair blastocysts obtained. Despite similar fertilization rate and number/quality of embryos, a reduction in ongoing pregnancy rate was observed in patients affected, possibly due to an altered endometrial receptivity or to the limited value of the conventional morphological evaluation of the embryo.

Endometriosis - a decade later - still an enigmatic disease. What is the new in the diagnosis and treatment?

Endometriosis is a common disease in women of reproduction age. It causes pain and difficulty in getting pregnant. However the exact causes of infertility associated with endometriosis still remain controversial. The treatment of endometriosis consists of medical treatment of pain as well as medical and surgical treatment of infertility caused by endometriosis and assisted reproduction techniques. Since the treatment of endometriosis is often connected with diminishing ovarian reserve, the techniques for ovarian tissue preservation and oocyte and embryo freezing are used to maintain the ability for childbearing.

Analysis of IVF/ICSI-FET Outcomes in Women With Advanced Endometriosis: Influence on Ovarian Response and Oocyte Competence

Aims: To determine the impact of advanced endometriosis (EMS) on in vitro fertilization/intracytoplasmic sperm injection and frozen-thawed embryo transfer (IVF/ICSI-FET) outcomes and analyze the influencing factors. Methods: A retrospective study was conducted on sterile women with ovarian endometriomas (OMAs), including patients who underwent laparoscopic cystectomy (n = 224, 224 IVF/ICSI cycles, 205 FET cycles) and aspiration (n = 139, 139 IVF/ICSI cycles, 148 FET cycles); peritoneal EMS (n = 96, 96 IVF/ICSI cycles, 89 FET cycles); and tubal factors (n = 360, 360 IVF/ICSI cycles, 474 FET cycles). Our main outcomes included the number of MII oocytes retrieved, fertilization rate, the number of viable embryos, viable embryo rate per oocyte retrieved in oocyte retrieval cycles, and clinical pregnancy rate per transfer, live birth rate per transfer, and cumulative clinical pregnancy rate of this oocyte retrieval cycle in FET cycles. Finally, binary logistic regression analysis was performed to generate a prediction model for cumulative clinical pregnancy. Results: The results showed that significantly fewer MII oocytes retrieved and viable embryos and lower viable embryo rate and cumulative clinical pregnancy rate were observed in women with EMS compared with the control. Women with peritoneal EMS had lower fertilization rate and viable embryo rate per oocyte retrieved than patients with OMA (all p < 0.05). However, the pregnancy outcomes were not significantly different between the two phenotypes. The patients who underwent laparoscopic cystectomy had fewer MII oocytes retrieved and viable embryos compared with those with intact endometrioma(s) but no significant difference in pregnancy outcomes between the two types of OMA patients. By binary logistic regression analysis, antral follicle count (AFC) was found to be an independent factor associated with cumulative clinical pregnancy in this oocyte retrieval cycle (odds ratio = 1.054; 95% confidence interval, 1.011-1.100; p = 0.014), and the AFC prediction model of cumulative clinical pregnancy was established, with an area under the curve of 0.60. Conclusions: Our data supported that advanced EMS has negative effect on cumulative clinical pregnancy per oocyte retrieval cycle, and AFC is an independent predictor, which is mainly caused by poor ovarian response associated with OMA per se or its surgery and the damage of peritoneal EMS to oocyte maturation.

Rethinking mechanisms, diagnosis and management of endometriosis

Endometriosis is a chronic inflammatory disease defined as the presence of endometrial tissue outside the uterus, which causes pelvic pain and infertility. This disease should be viewed as a public health problem with a major effect on the quality of life of women as well as being a substantial economic burden. In light of the considerable progress with diagnostic imaging (for example, transvaginal ultrasound and MRI), exploratory laparoscopy should no longer be used to diagnose endometriotic lesions. Instead, diagnosis of endometriosis should be based on a structured process involving the combination of patient interviews, clinical examination and imaging. Notably, a diagnosis of endometriosis often leads to immediate surgery. Therefore, rethinking the diagnosis and management of endometriosis is warranted. Instead of assessing endometriosis on the day of the diagnosis, gynaecologists should consider the patient's 'endometriosis life'. Medical treatment is the first-line therapeutic option for patients with pelvic pain and no desire for immediate pregnancy. In women with infertility, careful consideration should be made regarding whether to provide assisted reproductive technologies prior to performing endometriosis surgery. Modern endometriosis management should be individualized with a patient-centred, multi-modal and interdisciplinary integrated approach.

Assisted reproductive technology treatment and risk of ovarian cancer—a nationwide population-based cohort study

STUDY QUESTION

Does hormone stimulation during assisted reproductive technology (ART) treatment increase the risk of ovarian cancer?

SUMMARY ANSWER

No increased risk of ovarian cancer was found among ART-treated women, with the exception of ART-treated women with endometriosis.

WHAT IS KNOWN ALREADY

Previous studies on the association between ovarian stimulation during ART and ovarian cancer have shown conflicting results. The risk of ovarian cancer varies according to the cause of infertility, and only a few studies on ART treatment and risk of ovarian cancer have had sufficient data to address this issue. Endometriosis has been linked to an increased risk of ovarian cancer.

STUDY DESIGN, SIZE, DURATION

Women undergoing ART treatment during 1994–2015 were registered in the Danish IVF register. Data were linked with data from the Danish Cancer Register and socio-demographic population registers using an individual person identification number assigned to people residing in Denmark.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women undergoing ART treatment were age-matched with a random sample of the female background population and followed for up to 22 years. After relevant exclusions, the population consisted of 58 472 ART-treated women and 625 330 untreated women, all with no previous malignancies. Ovarian cancer risk was assessed using multivariable cox regression analyses with adjustment for educational level, marital status, parity and treatment year. Results are shown as hazard ratios (HRs) with corresponding CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 393 (0.06%) women were diagnosed with ovarian cancer during follow-up (mean 9.7 years). Women treated with ART had an increased risk of ovarian cancer (HR 1.20, 95% CI 1.10–1.31), which diminished over time. The increased risk was apparent among women with female factor infertility (HR 1.36, 95% CI 1.25–1.48), whereas no female factor infertility was associated with a lower risk (HR 0.87, 95% CI 0.76–1.00). The risk was increased among women with endometriosis (HR 3.78, 95% CI 2.45–5.84), whereas no increased risk was found among ART-treated women with polycystic ovary syndrome, other female causes of infertility and unexplained infertility.

LIMITATIONS, REASONS FOR CAUTION

The association between ART treatment and ovarian cancer is likely influenced by increased detection due to multiple ultrasound scans during ART treatment.

WIDER IMPLICATIONS OF THE FINDINGS

Undergoing ART treatment without the presence of endometriosis was not associated with an increased risk of ovarian cancer, which is reassuring. Whether ART treatment increases the risk of ovarian cancer among women with endometriosis needs further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a PhD grant to D.V. from the Faculty of Health and Medical Sciences, University of Copenhagen, Denmark. Funding for establishing the Danish National ART-couple II cohort was achieved from Ebba Rosa Hansen Foundation. The funders had no influence on data collection, analyses or results presented. The authors have no conflicts of interest to declare.

Endometriosis

Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.