Reproductive performance after the application of hyaluronic acid gel after dilation and curettage in women who have experienced at least one previous curettage: long-term results of a multicenter prospective randomized trial

Effects and safety of hyaluronic acid gel on intrauterine adhesion and fertility after intrauterine surgery: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials

OBJECTIVE

This study aimed to determine the efficacy and safety of hyaluronic acid gel for the prevention of intrauterine adhesions and improved fertility after intrauterine surgery.

DATA SOURCES

PubMed, EMBASE, Cochrane Library, Web of science, and ClinicalTrials.gov were searched up to November 1, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that reported intrauterine adhesion and fertility outcomes among women who used hyaluronic acid after intrauterine surgery.

METHODS

The risk of bias was assessed using criteria of the Cochrane Handbook, and the quality of the evidence was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation system. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A trial sequential analysis was conducted to assess the outcomes, and Stata 14 was used for sensitivity analyses and publication bias analyses.

RESULTS

Data from 16 randomized controlled trials involving 2359 patients were extracted and analyzed. The analysis revealed that hyaluronic acid reduced the incidence of intrauterine adhesion (risk ratio, 0.53; 95% confidence interval, 0.42-0.67; I2=48%) and improve pregnancy rates (risk ratio, 1.24; 95% confidence interval, 1.02-1.50; I2=0%). A subgroup analysis was conducted to evaluate factors that influence the effect of hyaluronic acid on the incidence of intrauterine adhesion. It was found that a small volume of hyaluronic acid reduced the incidence of intrauterine adhesions. Hyaluronic acid exhibited a protective effect among patients who underwent various intrauterine surgeries and who had different gynecologic medical histories. The protective effect was statistically significant after a follow-up of 6 to 12 weeks. The results of the trial sequential analysis indicated that the effect of hyaluronic acid on the incidence of mild intrauterine adhesions, pregnancy rates, live birth rates, and miscarriage rates after intrauterine surgery may be inconclusive and thus further evaluation is required in the form of additional clinical trials. However, the remaining effects were found to be verifiable and did not require more clinical trials for confirmation.

CONCLUSION

Hyaluronic acid can safely and effectively reduce the incidence of intrauterine adhesions and may improve fertility outcomes.

Effect of autologous bone marrow stem cells-scaffold transplantation on the ongoing pregnancy rate in intrauterine adhesion women: a randomized, controlled trial

Intrauterine adhesion is a major cause of female reproductive disorders. Although we and others uncontrolled pilot studies showed that treatment with autologous bone marrow stem cells made a few patients with severe intrauterine adhesion obtain live birth, no large sample randomized controlled studies on this therapeutic strategy in such patients have been reported so far. To verify if the therapy of autologous bone marrow stem cells-scaffold is superior to traditional treatment in moderate to severe intrauterine adhesion patients in increasing their ongoing pregnancy rate, we conducted this randomized controlled clinical trial. Totally 195 participants with moderate to severe intrauterine adhesion were screened and 152 of them were randomly assigned in a 1:1 ratio to either group with autologous bone marrow stem cells-scaffold plus Foley balloon catheter or group with only Foley balloon catheter (control group) from February 2016 to January 2020. The per-protocol analysis included 140 participants: 72 in bone marrow stem cells-scaffold group and 68 in control group. The ongoing pregnancy occurred in 45/72 (62.5%) participants in the bone marrow stem cells-scaffold group which was significantly higher than that in the control group (28/68, 41.2%) (RR=1.52, 95%CI 1.08-2.12, P=0.012). The situation was similar in live birth rate (bone marrow stem cells-scaffold group 56.9% (41/72) vs. control group 38.2% (26/68), RR=1.49, 95%CI 1.04-2.14, P=0.027). Compared with control group, participants in bone marrow stem cells-scaffold group showed more menstrual blood volume in the 3rd and 6th cycles and maximal endometrial thickness in the 6th cycle after hysteroscopic adhesiolysis. The incidence of mild placenta accrete was increased in bone marrow stem cells-scaffold group and no severe adverse effects were observed. In conclusion, transplantation of bone marrow stem cells-scaffold into uterine cavities of the participants with moderate to severe intrauterine adhesion increased their ongoing pregnancy and live birth rates, and this therapy was relatively safe.

Hysteroscopy-assisted suction curettage for early pregnancy loss: does it reduce retained products of conception and postoperative intrauterine adhesions?

OBJECTIVE

To describe the feasibility of hysteroscopy-assisted suction curettage for early pregnancy loss and to investigate whether it reduces the rates of retained products of conception (RPOC) and intrauterine adhesions (IUA).

DESIGN

Prospective single-arm cohort study.

SETTING

University-affiliated Department of Obstetrics and Gynecology.

PATIENTS

Women admitted for surgical evacuation of early pregnancy loss were invited to participate in the study.

INTERVENTION

Vaginal misoprostol was administered for cervical ripening preoperatively. Under general anesthesia, a diagnostic hysteroscopy was performed to identify the pregnancy's implantation wall, followed by ultrasound-guided suction and curettage directed to the implantation wall, and then diagnostic hysteroscopy to verify complete uterine cavity emptying. Postoperative IUA were evaluated by follow-up office hysteroscopy.

MAIN OUTCOME MEASURE

Identification of the pregnancy's implantation wall on hysteroscopy, and intra-, and postoperative complications associated with the procedure. The evaluation of postoperative IUA was limited due to the COVID-19 pandemic-related restrictions on elective procedures.

RESULTS

Forty patients were included in the study group. Their mean age was 34.0 ± 6.6 years, and their mean gestational age was 8.9 ± 1.6 weeks. The implantation wall was clearly visualized on hysteroscopy in 33 out of 40 cases (82.5%). The mean operative time was 17.2 ± 8.8 min, and no intraoperative complications occurred. Suspected RPOC were diagnosed intraoperatively by hysteroscopy and removed in 4 cases, and the histologic examination confirmed the presence of RPOC in three of them. Follow-up office hysteroscopy was performed in nine women: mild IUA was diagnosed in one case and a normal cavity was confirmed in eight cases. A new pregnancy was reported at the time of follow-up in 15 cases, while 12 women declined to attend the follow-up hysteroscopy and four were lost to follow-up.

CONCLUSIONS

Hysteroscopy-assisted suction curettage for early pregnancy loss is a safe, short, and inexpensive procedure, which allows the identification of the pregnancy's wall in most cases and may reduce the rates of RPOC.

Cyclical endometrial repair and regeneration: Molecular mechanisms, diseases, and therapeutic interventions

The endometrium is a unique human tissue with an extraordinary ability to undergo a hormone-regulated cycle encompassing shedding, bleeding, scarless repair, and regeneration throughout the female reproductive cycle. The cyclical repair and regeneration of the endometrium manifest as changes in endometrial epithelialization, glandular regeneration, and vascularization. The mechanisms encompass inflammation, coagulation, and fibrinolytic system balance. However, specific conditions such as endometriosis or TCRA treatment can disrupt the process of cyclical endometrial repair and regeneration. There is uncertainty about traditional clinical treatments' efficacy and side effects, and finding new therapeutic interventions is essential. Researchers have made substantial progress in the perspective of regenerative medicine toward maintaining cyclical endometrial repair and regeneration in recent years. Such progress encompasses the integration of biomaterials, tissue-engineered scaffolds, stem cell therapies, and 3D printing. This review analyzes the mechanisms, diseases, and interventions associated with cyclical endometrial repair and regeneration. The review discusses the advantages and disadvantages of the regenerative interventions currently employed in clinical practice. Additionally, it highlights the significant advantages of regenerative medicine in this domain. Finally, we review stem cells and biologics among the available interventions in regenerative medicine, providing insights into future therapeutic strategies.

Recent Developments in Biomaterial-Based Hydrogel as the Delivery System for Repairing Endometrial Injury

Endometrial injury caused by intrauterine surgery often leads to pathophysiological changes in the intrauterine environment, resulting in infertility in women of childbearing age. However, clinical treatment strategies, especially for moderate to severe injuries, often fail to provide satisfactory therapeutic effects and pregnancy outcomes. With the development of reproductive medicine and materials engineering, researchers have developed bioactive hydrogel materials, which can be used as a physical anti-adhesion barrier alone or as functional delivery systems for intrauterine injury treatment by loading stem cells or various active substances. Studies have demonstrated that the biomaterial-based hydrogel delivery system can provide sufficient mechanical support and improve the intrauterine microenvironment, enhance the delivery efficiency of therapeutic agents, prolong intrauterine retention time, and perform efficiently targeted repair compared with ordinary drug therapy or stem cell therapy. It shows the promising application prospects of the hydrogel delivery system in reproductive medicine. Herein, we review the recent advances in endometrial repair methods, focusing on the current application status of biomaterial-based hydrogel delivery systems in intrauterine injury repair, including preparation principles, therapeutic efficacy, repair mechanisms, and current limitations and development perspectives.

DOES HYALURONIC ACID GEL REDUCE INTRAUTERINE ADHESIONS AFTER DILATION AND CURETTAGE IN WOMEN WITH MISCARRIAGE? MULTICENTRIC RANDOMIZED CONTROLLED TRIAL (HYFACO STUDY)

BACKGROUND

Miscarriage is a frequent problem that requires dilation and curettage in 30 % of cases. This routine surgery may lead to intrauterine adhesions and severe infertility. Hyaluronic acid gel is known to reduce intrauterine adhesions after hysteroscopic surgery.

OBJECTIVE

This study aimed to evaluate the rate of intrauterine adhesions after dilation and curettage for miscarriage with and without hyaluronic acid gel.

STUDY DESIGN

This was a multicentric (nine hospitals in France), prospective, open-labelled randomized trial. Patients who had a miscarriage between weeks 7 and 14 of gestation, requiring dilation and curettage, and who were wishing for another pregnancy were eligible for the study. Women were randomly assigned 1:1 to surgery alone (control group) vs surgery with intrauterine instillation of hyaluronic acid gel (gel group). An office hysteroscopy was planned six to eight weeks after surgery. The primary endpoint was the rate of intrauterine adhesions during this office follow-up hysteroscopy. Two different follow-up fertility surveys were sent at 6 months and one year after the end of the intervention respectively.

RESULTS

Among the 343 patients who had curettage, 278 had hysteroscopy. After multiple imputation, the rate of intrauterine adhesions was lower in the gel group compared to the control group (9.1% vs. 18.4%, respectively, p=0.0171). Among the 110 responders to the surveys, the overall pregnancy rate twelve months after surgery was 64.5% (71/110), and similar in both groups (57.4 % (27/47) in control group vs. 69.8% (44/63) in gel group, p=0.1789).

CONCLUSION

Intrauterine instillation of hyaluronic acid gel reduces the rate of intrauterine adhesions in women treated with dilation and curettage for miscarriage.

Bioactive NIR-II Light-Responsive Shape Memory Composite Based on Cuprorivaite Nanosheets for Endometrial Regeneration

Intrauterine adhesions (IUAs) caused by mechanical damage or infection increase the risk of infertility in women. Although numerous physical barriers such as balloon or hydrogel are developed for the prevention of IUAs, the therapeutic efficacy is barely satisfactory due to limited endometrial healing, which may lead to recurrence. Herein, a second near-infrared (NIR-II) light-responsive shape memory composite based on the combination of cuprorivaite (CaCuSi₄ O₁₀ ) nanosheets (CUP NSs) as photothermal conversion agents and polymer poly(d,l-lactide-co-trimethylene carbonate) (PT) as shape memory building blocks is developed. The as-prepared CUP/PT composite possesses excellent shape memory performance under NIR-II light, and the improved operational feasibility as an antiadhesion barrier for the treatment of IUAs. Moreover, the released ions (Cu, Si) can stimulate the endometrial regeneration due to the angiogenic bioactivity. This study provides a new strategy to prevent IUA and restore the injured endometrium relied on shape memory composite with enhanced tissues reconstruction ability.

Decision tree model predicts live birth after surgery for moderate-to-severe intrauterine adhesions

Background

After treatment of intrauterine adhesions, the rate of re-adhesion is high and the pregnancy outcome unpredictable and unsatisfactory. This study established and verified a decision tree predictive model of live birth in patients after surgery for moderate-to-severe intrauterine adhesions (IUAs).

Methods

A retrospective observational study initially comprised 394 patients with moderate-to-severe IUAs diagnosed via hysteroscopy. The patients underwent hysteroscopic adhesiolysis from January 2013 to January 2017, in a university-affiliated hospital. Follow-ups to determine the rate of live birth were conducted by telephone for at least the first postoperative year. A classification and regression tree algorithm was applied to establish a decision tree model of live birth after surgery.

Results

Within the final population of 374 patients, the total live birth rate after treatment was 29.7%. The accuracy of the model was 83.8%, and the area under the receiver operating characteristic curve (AUC) was 0.870 (95% CI 7.699–0.989). The root node variable was postoperative menstrual pattern. The predictive accuracy of the multivariate logistic regression model was 70.3%, and the AUC was 0.835 (95% CI 0.667–0.962).

Conclusions

The decision tree predictive model is useful for predicting live birth after surgery for IUAs; postoperative menstrual pattern is a key factor in the model. This model will help clinicians make appropriate clinical decisions during patient consultations.

Bioengineered endometrial hydrogels with growth factors promote tissue regeneration and restore fertility in murine models

Extracellular matrix (ECM) hydrogels obtained from decellularized tissues are promising biocompatible materials for tissue regeneration. These biomaterials may provide important options for endometrial pathologies such as Asherman's syndrome and endometrial atrophy, which lack effective therapies thus far. First, we performed a proteomic analysis of a decellularized endometrial porcine hydrogel (EndoECM) to describe the specific role of ECM proteins related to regenerative processes. Furthermore, we investigated the ability of a bioengineered system-EndoECM alone or supplemented with growth factors (GFs)-to repair the endometrium in a murine model of endometrial damage. For this model, the uterine horns of female C57BL/6 mice were first injected with 70% ethanol, then four days later, they were treated with: saline (negative control); biotin-labeled EndoECM; or biotin-labeled EndoECM plus platelet-derived GF, basic fibroblast GF, and insulin-like GF 1 (EndoECM+GF). Endometrial regeneration and fertility restoration were evaluated by assessing the number of glands, endometrial area, cell proliferation, neaoangiogenesis, reduction of collagen deposition, and fertility restoration. Interestingly, regenerative effects such as an increased number of endometrial glands, increased area, high cell proliferative index, development of new blood vessels, reduction of collagen deposition, and higher pregnancy rate occurred in mice treated with EndoECM+GF. Thus, a bioengineered system based on EndoECM hydrogel supplemented with GFs may be promising for the clinical treatment of endometrial conditions such as Asherman's syndrome and endometrial atrophy. STATEMENT OF SIGNIFICANCE: In the last years, the bioengineering field has developed new and promising approaches to regenerate tissues or replace damaged and diseased tissues. Bioengineered hydrogels offer an ideal option because these materials can be used not only as treatments but also as carriers of drugs and other therapeutics. The present work demonstrates for the first time how hydrogels derived from pig endometrium loaded with growth factors could treat uterine pathologies in a mouse model of endometrial damage. These findings provide scientific evidence about bioengineered hydrogels based on tissue-specific extracellular matrix offering new options to treat human infertility from endometrial causes such as Asherman's syndrome or endometrial atrophy.

Focus on the Primary Prevention of Intrauterine Adhesions: Current Concept and Vision

Intrauterine adhesion (IUA), and its severe form Asherman syndrome (Asherman’s syndrome), is a mysterious disease, often accompanied with severe clinical problems contributing to a significant impairment of reproductive function, such as menstrual disturbance (amenorrhea), infertility or recurrent pregnancy loss. Among these, its correlated infertility may be one of the most challenging problems. Although there are many etiologies for the development of IUA, uterine instrumentation is the main cause of IUA. Additionally, more complicated intrauterine surgeries can be performed by advanced technology, further increasing the risk of IUA. Strategies attempting to minimize the risk and reducing its severity are urgently needed. The current review will expand the level of our knowledge required to face the troublesome disease of IUA. It is separated into six sections, addressing the introduction of the normal cyclic endometrial repairing process and its abruption causing the formation of IUA; the etiology and prevalence of IUA; the diagnosis of IUA; the classification of IUA; the pathophysiology of IUA; and the primary prevention of IUA, including (1) delicate surgical techniques, such as the use of surgical instruments, energy systems, and pre-hysteroscopic management, (2) barrier methods, such as gels, intrauterine devices, intrauterine balloons, as well as membrane structures containing hyaluronate–carboxymethylcellulose or polyethylene oxide–sodium carboxymethylcellulose as anti-adhesive barrier.

Anti-adhesion Gel versus No gel following Operative Hysteroscopy prior to Subsequent fertility Treatment or timed InterCourse (AGNOHSTIC), a randomised controlled trial: protocol

STUDY QUESTIONS

Does the application of anti-adhesion gel, compared to no gel, following operative hysteroscopy to treat intrauterine pathology in women wishing to conceive increase the chance of conception leading to live birth?

WHAT IS KNOWN ALREADY

Intrauterine adhesions (IUAs) following operative hysteroscopy may impair reproductive success in women of reproductive age. Anti-adhesion barrier gels may decrease the occurrence of IUAs, but the evidence on their effectiveness to improve reproductive outcomes is sparse and of low quality.

STUDY DESIGN SIZE DURATION

This multicentre, parallel group, superiority, blinded and pragmatic randomised controlled trial is being carried out in seven participating centres in Belgium. Recruitment started in April 2019. Women will be randomly allocated to treatment with anti-adhesion gel (intervention group) or no gel (control group). Sterile ultrasound gel will be applied into the vagina as a mock-procedure in both treatment arms. The patient, fertility physician and gynaecologist performing the second-look hysteroscopy are unaware of the allocated treatment. Power analysis, based on a target improvement of 15% in conception leading to live birth using anti-adhesion gel, a power of 85%, a significance level of 5%, and a drop-out rate of 10%, yielded a number of 444 patients to be randomised. The baseline rate of conception leading to live birth in the control group is expected to be 45%.

PARTICIPANTS/MATERIALS SETTING METHODS

Women of reproductive age (18-47 years), wishing to conceive (spontaneously or by fertility treatment) and scheduled for operative hysteroscopy to treat intrauterine pathology (endometrial polyps, myomas with uterine cavity deformation, uterine septa, IUAs or retained products of conception) are eligible for recruitment. Women may try to conceive from 3 to 6 weeks after receiving allocated treatment with follow-up ending at 30 weeks after treatment. If the woman fails to conceive within this timeframe, a second-look hysteroscopy will be scheduled within 2-6 weeks to check for IUAs. The primary endpoint is conception leading to live birth, measured at 30 weeks after randomisation. The secondary endpoints are time to conception, clinical pregnancy, miscarriage and ectopic pregnancy rates, measured at 30 weeks after receiving allocated treatment. The long-term follow-up starts when the patient is pregnant and she will be contacted every trimester.

STUDY FUNDING/COMPETING INTERESTS

This work is funded by the Belgian Healthcare Knowledge Centre (KCE). The anti-adhesion gel is supplied at no cost by Nordic Pharma and without conditions. Dr. Tomassetti reports grants and non-financial support from Merck SA, non-financial support from Ferring SA, personal fees and non-financial support from Gedeon-Richter, outside the submitted work. None of the other authors have a conflict of interest.

Application of Hydrogel-Based Delivery System in Endometrial Repair

A receptive endometrium with proper thickness is essential for successful embryo implantation. However, endometrial injury caused by intrauterine procedures often leads to pathophysiological changes in its environment, resulting in subsequent female infertility. Among diverse treatment methods of endometrial injury, hydrogels are a class of hydrophilic three-dimensional polymeric network with biocompatibility as well as the capability of absorbing water and encapsulation, which have potential applications as a promising intrauterine controlled-release delivery system. This review summarizes recent advances in the approaches of endometrial repair and further focuses on the application of a hydrogel-based delivery system in endometrial repair, including its preparation, therapeutic loading considerations, clinical applications, as well as working mechanisms.

Pregnancy and neonatal outcomes 42 months after application of hyaluronic acid gel following dilation and curettage for miscarriage in women who have experienced at least one previous curettage: follow-up of a randomized controlled trial

OBJECTIVE

To study whether intrauterine application of auto-crosslinked polymers of hyaluronic acid (ACP) gel after dilation and curettage (D&C) improves reproductive outcomes.

DESIGN

Follow-up of a prospective randomized trial.

SETTING

University and university-affiliated teaching hospitals.

PATIENT(S)

Women with a miscarriage at <14 weeks' gestation with at least one previous D&C were randomized to D&C plus ACP gel (intervention) or D&C alone (control). A hysteroscopy was performed after 8-12 weeks, and if intrauterine adhesion (IUAs) were encountered, adhesiolysis was executed.

INTERVENTION(S)

Participants received a questionnaire 30 months after treatment.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy and outcome of subsequent pregnancies.

RESULT(S)

Ongoing pregnancies were recorded in 74.6% (50/67) of the intervention group versus 67.2% (43/64) of the control group, and in, respectively, 94.3% (50/53) versus 71.7% (43/60) in the women wishing to conceive. The median times to conception leading to a live birth were, respectively, 21.9 versus 36.1 months. Reduced menstrual blood loss was reported in 7.5% (5/67) versus 20.3% (13/64) and dysmenorrhea in 14.9% (10/67) versus 34.4% (22/64), respectively.

CONCLUSION(S)

Application of ACP gel following D&C performed after miscarriage seems to have a favorable effect on subsequent reproductive outcomes in women with at least one previous D&C. Given the fact that the study was not powered for reproductive outcomes, the data should be interpreted with caution. The effect may be underestimated due to routine removal of IUAs.

DUTCH CLINICAL TRIAL REGISTRY NUMBER

NTR 3120.