Application of atosiban in frozen-thawed cycle patients with different times of embryo transfers

Improvement of early miscarriage rates in women with adenomyosis via oxytocin receptor antagonist during frozen embryo transfer-a propensity score-matched study

BACKGROUND

Dysfunctional uterine peristalsis seems to play a pivotal role in hindering embryo implantation among women diagnosed with adenomyosis. This research aims to investigate whether administering an oxytocin receptor antagonist during a frozen embryo transfer (FET) cycle using a hormone replacement therapy (HRT) protocol can enhance in vitro fertilization (IVF) outcomes for infertile women affected by adenomyosis.

METHODS

Between January 2018 and June 2022, our reproductive center conducted IVF-FET HRT cycles for infertile women diagnosed with adenomyosis. Propensity score matching was employed to select matched subjects between the two groups in a 1:1 ratio. Following this, 168 women received an oxytocin receptor antagonist during FET, constituting the study group, while the matched 168 women underwent FET without this antagonist, forming the control group. We conducted comparative analyses of baseline and cycle characteristics between the two groups, along with additional subgroup analyses.

RESULTS

The study group exhibited notably lower rates of early miscarriage compared to the control group, although there were no significant differences in clinical pregnancy rates, ongoing pregnancy rates, and live birth rates between the two groups. Multivariate analysis revealed a negative correlation between the use of oxytocin receptor antagonists and early miscarriage rates in women with adenomyosis. Subgroup analyses, categorized by age, infertility types, and embryo transfer day, showed a substantial decrease in early miscarriage rates within specific subgroups: women aged ≥ 37 years, those with secondary infertility, and individuals undergoing day 3 embryo transfers in the study group compared to the control group. Furthermore, subgroup analysis based on adenomyosis types indicated significantly higher clinical pregnancy rates, ongoing pregnancy rates and live birth rates in the study group compared to the control group among women with diffuse adenomyosis.

CONCLUSIONS

Administering an oxytocin receptor antagonist during FET may reduce the early miscarriage rates in women with adenomyosis.

Atosiban application in fresh ET cycle is effective for women undergoing repeated embryo implantation failures, especially for advanced-age obese patients

To assess the effect of atosiban in pregnancy outcomes of the fresh embryo transfer (ET), the retrospective cohort study was conducted. Six hundred and eighty-nine cases (using atosiban) and 1377 age and ET cycle-matched controls were collected from the January 2016 to May 2022 to perform the fresh IVF-ET cycle. The essential characteristics and pregnancy outcomes were analyzed. Conditional logistic regression analysis and subgroup analysis were performed. In the whole samples, atosiban had no effects in the pregnancy outcomes. Subgroup analyses suggested that atosiban could improve the clinical pregnancy in more than 3 ET cycles (OR 1.667, 95% CI 1.108-2.509, P = 0.014). Moreover, the improvement of clinical pregnancy was mainly present in the advanced-age women (age ≥ 35 years: OR 1.851, 95% CI 1.136-3.014, P = 0.013), obesity (BMI ≥ 24 kg/m2: OR 2.550, 95% CI 1.105-5.883, P = 0.028) and cleavage stage embryo (D3 embryo: OR 1.721, 95% CI 1.098-2.696, P = 0.018) among the repeated implantation failures (RIF). Atosiban could also improve the live birth for the obese women. Further, in the RIF, atosiban application was strongly recommended for the advanced-age infertility women, who also had the risk of obesity with the implantation of the cleavage stage embryo. In conclusion, atosiban could improve pregnancy outcomes for the advanced-age and obese women in RIF, especially while implanting the cleavage stage embryo in fresh ET cycle.

Effectiveness of atosiban in women with previous single implantation failure undergoing frozen-thawed blastocyst transfer: study protocol for a randomised controlled trial

BACKGROUND

Uterine contractions may interfere with embryo implantation in assisted reproductive technology. To reduce these contractions and improve success rates, the oxytocin antagonist atosiban has been suggested for administration during embryo transfer. The aim of this study is to evaluate the effectiveness of atosiban in increasing live birth rates among women who have previously experienced a single implantation failure and are scheduled for single blastocyst transfer.

METHODS AND ANALYSIS

We conduct a single-centre randomised controlled study comparing atosiban and placebo in women undergoing a single blastocyst transfer with a previous failed blastocyst transfer. Women with endocrine or systemic illnesses, recurrent miscarriages, uterine malformations or fibroids, untreated hydrosalpinx, endometriosis (stage III or IV) or uterine fibroids, as well as women undergoing preimplantation genetic testing, are ineligible. The primary outcome is live birth resulting from the frozen-thawed embryo transfer. Secondary outcomes include biochemical/clinical pregnancy, miscarriage, ectopic pregnancy, multiple pregnancies as well as maternal and perinatal outcomes. We plan to recruit 1100 women (550 women per group). This will allow us to demonstrate or refute an increase in live birth rate from 40% to 50%. Data analysis will follow the intention-to-treat principle. We will measure patterns of uterine peristalsis which will allow subgroup analysis for women with or without uterine peristalsis.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board of Northwest Women's and Children's Hospital (No. SZ2019001). Written informed consent will be obtained from each participant before randomisation. The results of the trial will be presented at scientific meetings and reported in publications.

TRIAL REGISTRATION NUMBER

ChiCTR1900022333.

Efficacy of atosiban for repeated implantation failure in frozen embryo transfer cycles

Atosiban was commonly added to improve pregnancy outcomes of patients with repeated embryo implantation failure (RIF). In this study, we aimed to investigate the effect of atosiban before transferring the frozen-thawed embryo to RIF patients. This retrospective study was conducted in the Hospital for Reproductive Medicine affiliated to Shandong University from August 2017 to June 2021. A total of 1774 women with a history of RIF undergoing frozen embryo transfer (FET) were included in this study. All the participants were classified into atosiban or control group: Group A included 677 patients who were administered atosiban intravenously 30 min prior to FET with a dose of 37.5 mg; Group B included 1097 patients who received no atosiban before the transfer. There were no significant differences observed in the live birth rate (LBR) (39.73% vs. 39.02%, P = 0.928) between the two groups. Other secondary outcomes including biochemical pregnancy rate, clinical pregnancy rate, implantation rate, clinical miscarriage rate and preterm birth rate were similar between the two groups (all P > 0.05). However, subgroup analysis demonstrated significantly higher preterm birth rates in the control group compared with the atosiban group (0 versus 3.0%, P = 0.024) in the natural FET cycles. Atosiban may not improve pregnancy outcomes of RIF patients in FET cycles. However, the effects of Atosiban on pregnancy outcomes should be assessed in clinical trials with larger sample sizes.

Efficacy of Platelet-Rich Plasma in Women with a History of Embryo Transfer Failure: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

Assisted reproductive technology (ART) is used to enhance pregnancy in infertile women. In this technique, the eggs are removed from the ovary and fertilized and injected with sperm to make embryos. Unfortunately, embryo implantation failures still occur in many of these women. Platelet-rich plasma (PRP) therapies use a patient's own platelets to promote tissue healing and growth, including endometrium. The growth factors provided by the platelets play a criterial role on the regenerative ability of PRP. In the last years, PRP treatments have been gaining a lot of popularity to treat women with repeated ART failures. In this study, we collected and summarized all information published in the scientific literature to assess the evidence of the PRP effect on pregnancy. We only considered randomized controlled trials (RCT), a type of study designed to be unbiased and considered at the highest level of evidence. Our analysis indicates that PRP therapies might be an effective treatment in cases of poor responsiveness to conventional ART. However, additional studies (well-designed) are necessary to confirm this beneficial effect of PRP.

Efficacy of atosiban for repeated embryo implantation failure: A systematic review and meta-analysis

BACKGROUND

Repeated embryo implantation failure (RIF) posed a significant challenge in assisted reproduction. Evidence of its therapeutic effectiveness including atosiban used around embryo transfer to improve pregnancy outcomes in RIF patients undergoing in vitro fertilization-embryo transfer (IVF-ET) remained inconsistent. This study aimed to explore the efficacy of atosiban on pregnancy outcomes of patients with RIF who received IVF-ET.

METHODS

The research was designed using the PICOS format. A systematic search of four English databases, PubMed, EMBASE, Web of Science, Cochrane Library, and one Chinse database, China National Knowledge Infrastructure (CNKI) was conducted. The time range was from inception to December 10, 2022. Then trials comparing the efficacy of atosiban and control group on pregnancy outcomes in RIF patients who receive IVF-ET were included. Subgroup analysis and sensitivity analysis were performed to reduce the influence of heterogeneity between included studies. Risk ratio (RR) and 95% confidence interval (CI) were calculated. The main outcome measure was clinical pregnancy rate (CPR). For the analyses, StataMP 17.0 (Stata Corporation, USA) was used.

RESULTS

Two prospective randomized controlled trials (RCTs), one prospective cohort study and four retrospective cohort studies were included. Our results showed that atosiban was associated with higher clinical pregnancy rate (RR=1.54, 95% CI: 1.365-1.735, P < 0.001, I^{2 =} 0.0%). The results of subgroup analysis based on study types (prospective randomized controlled clinical trial, retrospective cohort study and prospective cohort study) showed that in all types of studies, CPR of atosiban group was significantly higher than controlled group. The results of subgroup analysis based upon the diagnostic criteria of number of previous embryo transfer failures showed that the intervention of atosiban improved the CPR whether in participants with 2 previous ET failures or in participants with 3 previous ET failures. Nevertheless, the incidence of ectopic pregnancy, multiple pregnancy, and miscarriages were not significantly different between the case and control groups.

CONCLUSION

For women who are undergoing IVF-ET and have experienced repeated embryo implantation failure, atosiban may be an important factor in enhancing pregnancy outcomes. To confirm this conclusion, more thorough, prospective randomized controlled studies of sizable sample sizes with well design are required.

A randomized double blind comparison of atosiban in patients with recurrent implantation failure undergoing IVF treatment

BACKGROUND

Patients with recurrent implantation failure (RIF) may have more uterine contractions. Several observational studies suggested that atosiban administration around embryo transfer resulted in higher pregnancy rates in RIF patients. This study aimed to evaluate the effect of atosiban given before fresh embryo transfer on pregnancy outcomes of women with RIF.

METHODS

A prospective, randomized, double-blind controlled clinical trial was performed in IVF center of Shanghai First Maternity and Infant Hospital. According to a computer-generated randomization list, 194 infertile women with RIF received fresh embryo transfer between July 2017 and December 2019 were randomly allocated into the atosiban (n = 97) and the placebo (n = 97) groups. Women in the treatment group received atosiban intravenously about 30 min before embryo transfer with a bolus dose of 6.75 mg over one minute. Those in the placebo group received only normal saline infusion for the same duration.

RESULTS

There was no significant difference in the live birth rate between the atosiban and placebo groups (42.3% vs 35.1%, P = 0.302, RR = 1.206 (0.844-1.723)). No significant differences were found between the two groups in the positive pregnancy test, clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and implantation rates. Similar results were found when stratified by the number of embryos previously transferred, number of previous failed embryo transfers, frequency of endometrial peristalsis on embryo transfer day (≥ 3 waves/min) or serum estradiol (E₂) on the day of hCG above the median level. And, there was no correlation between the serum E₂ level on the day of hCG and the frequency of endometrial peristalsis on embryo transfer day. The frequency of endometrial peristalsis on embryo transfer day, total FSH/HMG dosage and duration were the significant factors which independently predicted the likelihood of a live birth.

CONCLUSIONS

These results suggested that atosiban treatment before fresh embryo transfer might not improve the live birth rate in RIF patients.

TRIAL REGISTRATION

The study had been approved by the Institutional Review Board of the hospital (2017 ethics No.43) and was registered under Clinicaltrials.gov with an identifier NCT02893722.

Oxytocin antagonists for assisted reproduction

BACKGROUND

Embryo transfer (ET) is a crucial step of in vitro fertilisation (IVF) treatment, and involves placing the embryo(s) in the woman's uterus. There is a negative association between endometrial wave-like activity (contractile activities) at the time of ET and clinical pregnancy, but no specific treatment is currently used in clinical practice to counteract their effects. Oxytocin is a hormone produced by the hypothalamus and released by the posterior pituitary. Its main role involves generating uterine contractions during and after childbirth. Atosiban is the best known oxytocin antagonist (and is also a vasopressin antagonist), and it is commonly used to delay premature labour by halting uterine contractions. Other oxytocin antagonists include barusiban, nolasiban, epelsiban, and retosiban. Administration of oxytocin antagonists around the time of ET has been proposed as a means to reduce uterine contractions that may interfere with embryo implantation. The intervention involves administering the medication before, during, or after the ET (or a combination).

OBJECTIVES

To evaluate the effectiveness and safety of oxytocin antagonists around the time of ET in women undergoing assisted reproduction.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two trials registers in March 2021; and checked references and contacted study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of the use of oxytocin antagonists for women undergoing ET, compared with the non-use of this intervention, the use of placebo, or the use of another similar drug.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Primary review outcomes were live birth and miscarriage; secondary outcomes were clinical pregnancy and other adverse events.

MAIN RESULTS

We included nine studies (including one comprising three separate trials, 3733 women analysed in total) investigating the role of three different oxytocin antagonists administered intravenously (atosiban), subcutaneously (barusiban), or orally (nolasiban). We found very low- to high-certainty evidence: the main limitations were serious risk of bias due to poor reporting of study methods, and serious or very serious imprecision. Intravenous atosiban versus normal saline or no intervention We are uncertain of the effect of intravenous atosiban on live birth rate (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.88 to 1.24; 1 RCT, N = 800; low-certainty evidence). In a clinic with a live birth rate of 38% per cycle, the use of intravenous atosiban would be associated with a live birth rate ranging from 33.4% to 47.1%. We are uncertain whether intravenous atosiban influences miscarriage rate (RR 1.08, 95% CI 0.75 to 1.56; 5 RCTs, N = 1424; I² = 0%; very low-certainty evidence). In a clinic with a miscarriage rate of 7.2% per cycle, the use of intravenous atosiban would be associated with a miscarriage rate ranging from 5.4% to 11.2%. Intravenous atosiban may increase clinical pregnancy rate (RR 1.50, 95% CI 1.18 to 1.89; 7 RCTs, N = 1646; I² = 69%; low-certainty evidence), and we are uncertain whether multiple or ectopic pregnancy and other complication rates were influenced by the use of intravenous atosiban (very low-certainty evidence). Subcutaneous barusiban versus placebo One study investigated barusiban, but did not report on live birth or miscarriage. We are uncertain whether subcutaneous barusiban influences clinical pregnancy rate (RR 0.96, 95% CI 0.69 to 1.35; 1 RCT, N = 255; very low-certainty evidence). Trialists reported more mild to moderate injection site reactions with barusiban than with placebo, but there was no difference in severe reactions. They reported no serious drug reactions; and comparable neonatal outcome between groups. Oral nolasiban versus placebo Nolasiban does not increase live birth rate (RR 1.13, 95% CI 0.99 to 1.28; 3 RCTs, N = 1832; I² = 0%; high-certainty evidence). In a clinic with a live birth rate of 33% per cycle, the use of oral nolasiban would be associated with a live birth rate ranging from 32.7% to 42.2%. We are uncertain of the effect of oral nolasiban on miscarriage rate (RR 1.45, 95% CI 0.73 to 2.88; 3 RCTs, N = 1832; I² = 0%; low-certainty evidence). In a clinic with a miscarriage rate of 1.5% per cycle, the use of oral nolasiban would be associated with a miscarriage rate ranging from 1.1% to 4.3%. Oral nolasiban improves clinical pregnancy rate (RR 1.15, 95% CI 1.02 to 1.30; 3 RCTs, N = 1832; I² = 0%; high-certainty evidence), and probably does not increase multiple or ectopic pregnancy, or other complication rates (moderate-certainty evidence).

AUTHORS' CONCLUSIONS

We are uncertain whether intravenous atosiban improves pregnancy outcomes for women undergoing assisted reproductive technology. This conclusion is based on currently available data from seven RCTs, which provided very low- to low-certainty evidence across studies. We could draw no clear conclusions about subcutaneous barusiban, based on limited data from one RCT. Further large well-designed RCTs reporting on live births and adverse clinical outcomes are still required to clarify the exact role of atosiban and barusiban before ET. Oral nolasiban appears to improve clinical pregnancy rate but not live birth rate, with an uncertain effect on miscarriage and adverse events. This conclusion is based on a phased study comprising three trials that provided low- to high-certainty evidence. Further large, well-designed RCTs, reporting on live births and adverse clinical outcomes, should focus on identifying the subgroups of women who are likely to benefit from this intervention.

Comparison of frozen-thawed embryo transfer protocols in patients with previous cycle cancellation due to uterine peristalsis: a pilot study

Background/aim

To investigate the optimal protocol for frozen-thawed embryo transfer (FET) cycles in patients who previously had a cycle cancellation due to uterine peristalsis (UP).

Materials and methods

Thirty-four patients with previous embryo transfer (ET) cancellation due to UP during artificial cycle (AC) were included retrospectively. In the proceeding cycle, endometrium was prepared with AC (n: 23) in AC-FET group or with stimulated cycle that contains letrozole (L) (n: 11) in L-FET group. Intravenous bolus dose of 6.75 mg atosiban (Tractocile; Ferring Pharmaceuticals, Switzerland) injection was performed to all patients of AC-FET group due to UP ≥ 4/min on the planned ET day of proceeding cycle. Atosiban was not used in L-FET group. Primary outcome was live birth rate (LBR) per ET. Secondary outcomes were clinical pregnancy rate (CPR) per ET, implantation rate (IR), cycle cancellation rate.

Results

The baseline characteristics such as age, body mass index, antral follicle count, duration of infertility, and the number of prior in vitro fertilization attempts of each group were similar. The IR, CPR per ET, LBR per ET, CPR per cycle and LBR per cycle were significantly higher; cycle cancellation rates were significantly lower in L-FET group as compared to the AC-FET group.

Conclusion

Endometrial preparation with letrozole significantly improves CPR and LBR in FET cycles of patients with previous cycle cancellations due to UP.

Efficacy of therapies and interventions for repeated embryo implantation failure: a systematic review and meta-analysis

The aim of the present systematic review and meta-analysis was to assess the effect of the different therapeutic options for repeated embryo implantation failure (RIF) on a subsequent IVF cycle outcome. Twenty-two RCTs and nineteen observational studies were included. Pooling of results showed a beneficial effect of intrauterine PBMC infusion on both CPR (RR 2.18; 95% CI 1.58-3.00; p < 0.00001; OR 2.03; 95% CI 1.22-3.36; p = 0.006) and LBR (RR 2.41; 95% CI 1.40-4.16; p = 0.002; OR 3.73; 95% CI 1.13-12.29; p = 0.03), of subcutaneous G-CSF administration on CPR (RR 2.29; 95% CI 1.58-3.31; p < 0.0001) and of intrauterine PRP infusion on CPR (RR 2.45; 95% CI 1.55-3.86; p = 0.0001). Observational studies also demonstrated a positive effect of IVIG and intrauterine hCG infusion on both CPR and LBR and of atosiban on CPR. Studies investigating intrauterine G-CSF infusion, LMWH, intravenous intralipid, hysteroscopy, blastocyst-stage ET, ZIFT, PGT-A and AH failed to observe an impact on IVF outcome. The quality of the evidence that emerged from RCTs focused on intrauterine PBMC infusion and subcutaneous G-CSF administration was moderate. For all other therapies/interventions it varied from low to very low. In conclusion, intrauterine PBMC infusion and subcutaneous G-CSF administration are the most promising therapeutic options for RIF. However, further well conducted RCTs are necessary before their introduction into clinical practice.

Atosiban improves the outcome of embryo transfer. A systematic review and meta-analysis of randomized and non-randomized trials

OBJECTIVE

To estimate the effectiveness of Atosiban in improving the outcome after embryo transfer. The effectiveness of embryo transfer per cycle is still relatively low. One possible explanation might be uterine contractility that expels the transferred embryos. Atosiban improved the outcome of embryo transfer by reducing uterine contractility.

METHODS

Data sources: A systematic review of papers in English using MEDLINE and EMBASE (1990-2019). Search terms included Atosiban, embryo transfer. Study selection: We included studies that compared the outcomes of embryo transfer with Atosiban and a control group. Data Extracting: Independent extraction of papers by two authors, using predefined data fields, including study quality indicators.

RESULTS

All pooled analyses were based on a fixed-effect model. Four randomised controlled trials, including 1,025 women, and two non-randomised trials, including 686 patients, met our inclusion criteria. In both studies, the heterogeneity was moderate. Atosiban increased clinical pregnancy rates regardless of the indication for ART or type of embryo transferred. Pooled OR in randomized controlled trials reached 1.47 (1.18-1.82), and in non-randomised controlled trials it reached 1.50 (95% CI 1.10-2.05).

CONCLUSION

Atosiban appears to increase the clinical pregnancy rates in women undergoing embryo transfer.

Atosiban and Pregnancy Outcomes Following In Vitro Fertilization Treatment for Infertile Women Requiring One, Two, or More Embryo Transfer Cycles: A Longitudinal Cohort Study

We assessed the effect of atosiban on pregnancy outcomes following in vitro fertilization (IVF) treatment among infertile women requiring different numbers of embryo transfer (ET) cycles (i.e., one, two, and more than two ET cycles). A longitudinal cohort study was conducted by utilizing the data from the Assisted Reproductive Technology Center in a university tertiary hospital during 2007-2017. Patients receiving IVF treatment with at least one ET cycle were included. Pregnancy outcomes following IVF treatment, including biochemical, clinical, and ongoing pregnancies, were investigated. The association between atosiban and IVF pregnancy was assessed using logistic generalized estimating equation models, with adjustment for time-varying clinical characteristics (e.g., maternal age) across multiple ET cycles for an individual. 403 women with 838 ET cycles were included, where 165 patients required one ET cycle, 133 patients required two ET cycles (a total of 266 ET cycles), and 105 patients required more than two ET cycles (a total of 407 ET cycles). Atosiban use was not significantly associated with pregnancy outcomes among all study infertile women undergoing IVF treatment. However, the results for women requiring more than two ET cycles showed significantly increased pregnancy rates associated with atosiban use (i.e., odds ratios [95% confidence interval] of 4.40 [1.52, 12.73] and 2.85 [1.45, 5.60] for clinical and ongoing pregnancies, respectively). This association was not observed for the women requiring only one or two ET cycles. Atosiban is a potential treatment for enhancing IVF pregnancy, especially among infertile women requiring more than two ET cycles.

The abnormal expression of oxytocin receptors in the uterine junctional zone in women with endometriosis

BACKGROUND

The junctional zone (JZ), also called as the endometrial-myometrial junction, is related to peristaltic-like movements in the non-pregnant uterus. Hyperperistalsis and dysperistalsis of uterus constructions might underlie many important disorders such as dysmenorrhea, infertility, endometriosis, implantation failure. The major proteins for uterine contraction of the non-pregnant uterus may be Oxytocin (OT) and oxytocin receptor (OTR). The objective of this study was to inspect the expression of OTR in isthmic and mid-fundal parts of the uterine junctional zone at different stages of the follicular cycle in patients with and without endometriosis.

METHODS

Uterine biopsies containing endometrium and junctional zone were collected from the isthmic and mid-fundal parts of the anterior wall after hysterectomy. The OTR expression was evaluated by immunohistochemistry.

RESULTS

In the control uterus, OTR expression in the isthmic region was significantly higher than in the fundal region in the proliferative phase (p < 0.05) but significantly lower in the secretory phase (p < 0.05). And the expression of OTR in the proliferative phase was significantly higher than that in the secretory phase in both isthmic and fundal regions (p = 0.000 and 0.049, respectively). However, in endometriosis uteri, OTR expression in the isthmic region showed no significant difference with that in the fundal region in both proliferative and secretory phases (p = 0.597 and 0.736, respectively). In both isthmic and fundal regions, OTR expression was not significantly different between the proliferative phase and secretory phase (p = 0.084 and 0.222, respectively). OTR expression in fundal regions of revised ASRM I and II endometriosis were lower than that of revised ASRM III and IV (p = 0.049). In the fundal region of JZ, the expression of OTR in ovarian endometriosis was significantly lower than that in deep infiltrating endometriosis (p = 0.046). The expression level of OTR in the funds region is positively associated with the severity of dysmenorrhea in endometriosis group (r = 0.870, p < 0.05). Comparing to normal uteri, the expression of OTR in the secretory phase was significantly higher in the endometriosis uteri (p < 0.05). In the fundus of endometriosis uteri, OTR expression was significantly higher in both the proliferative and secretory phases (p = 0.045 and 0.028, respectively).

CONCLUSION

OTR expression in the JZ of women with endometriosis changes significantly, which may result in abnormal uterine contractile activity, reducing the endometriosis-related fertility and dysmenorrhea.