Prevalence of intrauterine adhesions after termination of pregnancy: a systematic review

Effect of emotion management and nursing on patients with painless induced abortion after operation

BACKGROUND

With an estimated 121 million abortions following unwanted pregnancies occurring worldwide each year, many countries are now committed to protecting women's reproductive rights.

AIM

To analyze the impact of emotional management and care on anxiety and contraceptive knowledge mastery in painless induced abortion (IA) patients.

METHODS

This study was retrospective analysis of 84 patients with IA at our hospital. According to different nursing methods, the patients were divided into a control group and an observation group, with 42 cases in each group. Degree of pain, rate of postoperative uterine relaxation, surgical bleeding volume, and postoperative bleeding volume at 1 h between the two groups of patients; nursing satisfaction; and mastery of contraceptive knowledge were analyzed.

RESULTS

After nursing, Self-Assessment Scale, Depression Self-Assessment Scale, and Hamilton Anxiety Scale scores were 39.18 ± 2.18, 30.27 ± 2.64, 6.69 ± 2.15, respectively, vs 45.63 ± 2.66, 38.61 ± 2.17, 13.45 ± 2.12, respectively, with the observation group being lower than the control group (P < 0.05). Comparing visual analog scales, the observation group was lower than the control group (4.55 ± 0.22 vs 3.23 ± 0.41; P < 0.05). The relaxation rate of the cervix after nursing, surgical bleeding volume, and 1-h postoperative bleeding volumes were 25 (59.5), 31.72 ± 2.23, and 22.41 ± 1.23, respectively, vs 36 (85.7), 42.39 ± 3.53, 28.51 ± 3.34, respectively, for the observation group compared to the control group. The observation group had a better nursing situation (P < 0.05), and higher nursing satisfaction and contraceptive knowledge mastery scores compared to the control group (P < 0.05).

CONCLUSION

The application of emotional management in postoperative care of IA has an ideal effect.

The efficacy of early office hysteroscopy in preventing intrauterine adhesions after abortion: a randomized controlled trial

BACKGROUND

Intrauterine adhesions (IUA) are a challenging clinical problem in reproductive infertility. The most common causes are intrauterine surgery and abortions. We aimed to investigate whether early second-look office hysteroscopy can prevent IUA.

METHODS

A single-center, prospective, two-armed, randomized controlled trial was designed to explore the efficacy of early office hysteroscopy after first-trimester induced abortion (suction dilatation and curettage [D&C]) and to further analyze fertility outcomes. Women aged 20-45 years undergoing suction D&C and desiring to conceive were recruited. Between October 2019 and September 2022, 66 women were enrolled, of whom 33 were allocated to group A (early hysteroscopy intervention). The women in intervention group A were planned to receive 2 times of hysteroscopies (early and late). In group B, women only underwent late (6 months post suction D&C) hysteroscopy.

RESULTS

The primary outcome was the IUA rate assessed using office hysteroscopy 6 months after artificial abortion. Secondary outcomes included menstrual amount/durations and fertility outcomes. In intervention group A, 31 women underwent the first hysteroscopy examination, and 15 completed the second. In group B (late hysteroscopy intervention, 33 patients), 16 completed the hysteroscopic exam 6 months after an artificial abortion. Twenty-one women did not receive late hysteroscopy due to pregnancy. The IUA rate was 16.1% (5/31) at the first hysteroscopy in group A, and no IUA was detected during late hysteroscopy. Neither group showed statistically significant differences in the follow-up pregnancy and live birth rates.

CONCLUSIONS

Early hysteroscopy following suction D&C can detect intrauterine lesions. IUA detected early by hysteroscopy can disappear on late examination and become insignificant for future pregnancies. Notably, the pregnancy outcomes showed a favorable trend in the early hysteroscopy group, but there were no statistically significant differences.

TRIAL REGISTRATION

ClinicalTrials.gov , ID: NCT04166500. Registered on 2019-11-10. https://clinicaltrials.gov/ct2/show/NCT04166500 .

β-Human Chorionic Gonadotropin Dynamics in Early Gestational Events: A Practical and Updated Reappraisal

In the last decade, the widespread use of transvaginal ultrasound and the availability of highly specific serum assays of human chorionic gonadotropin (hCG) have become mainstays in the evaluation of early pregnancy. These tests have revolutionized the management of pregnancies of unknown location and markedly reduced the morbidity and mortality associated with the misdiagnosis of ectopic pregnancy. However, despite several advances, their misuse and misinterpretations are still common, leading to an increased use of healthcare resources, patient misinformation, and anxiety. This narrative review aims to succinctly summarize the β-hCG dynamics in early gestation and provide general gynecologists a practical approach to patients with first-trimester symptomatic pregnancy.

Does repetitive dilatation and curettage or hysteroscopic biopsy in patients treated with progestins for endometrial hyperplasia or carcinoma affect subsequent fetomaternal outcomes? A population-based study using the National Health Insurance Research Database of Taiwan

OBJECTIVE

To investigate the impact of repeated dilatation and curettage or hysteroscopic biopsy on fetomaternal outcomes in patients receiving progestin treatment for endometrial hyperplasia or early-stage carcinoma.

METHOD

This was a population-based study using the Taiwan National Health Insurance Research Database between 2009 and 2017 of women who gave birth and had a history of endometrial hyperplasia and early-stage carcinoma treated with progestins. Logistic regression analysis was used to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs) reflecting the association between repeated procedures and fetomaternal outcomes.

RESULTS

A total of 6956 women with 8690 deliveries were identified. Compared with those who had two or fewer procedures, women who received more than two procedures had a significantly higher risk for cervical insufficiency (aOR, 5.09 [95 CI, 2.31-11.24]). Furthermore, women who had more than two procedures were prone to have adverse neonatal outcomes, including Apgar score < 7 at 1 min (aOR, 1.97 [95% CI, 1.13-3.43]) and 5 min (aOR, 3.11 [95% CI, 1.33-7.23]) and preterm delivery <32 weeks (aOR, 2.86 [95% CI, 1.50-5.45]).

CONCLUSION

Undergoing more than two procedures was associated with subsequent maternal cervical insufficiency, preterm delivery <32 weeks, and low neonatal Apgar score. Health care providers should be aware of the potential risks and balance the benefits and harms of repeated procedures.

A cost-effectiveness analysis of intrauterine spacers used to prevent the formation of intrauterine adhesions following endometrial cavity surgery

AIM

To assess, from a United States (US) payer's perspective, the cost-effectiveness of gels designed to separate the endometrial surfaces (intrauterine spacers) placed following intrauterine surgery.

MATERIALS AND METHODS

A decision tree model was developed to estimate the cost-effectiveness of intrauterine spacers used to facilitate endometrial repair and prevent the formation (primary prevention) and reformation (secondary prevention) of intrauterine adhesions (IUAs) and associated pregnancy- and birth-related adverse outcomes. Event rates and costs were extrapolated from data available in the existing literature. Sensitivity analyses were conducted to corroborate the base case results.

RESULTS

In this model, using intrauterine spacers for adhesion prevention led to net cost savings for US payers of $2,905 per patient over a 3.5-year time horizon. These savings were driven by the direct benefit of preventing procedures associated with IUA formation ($2,162 net savings) and the indirect benefit of preventing pregnancy-related complications often associated with IUA formation ($3,002). These factors offset the incremental cost of intrauterine spacer use of $1,539 based on an assumed price of $1,800 and the related increase in normal deliveries of $931. Model outcomes were sensitive to the probability of preterm and normal deliveries. Budget impact analyses show overall cost savings of $19.96 per initial member within a US healthcare plan, translating to $20 million over a 5-year time horizon for a one-million-member plan.

LIMITATIONS

There are no available data on the effects of intrauterine spacers or IUAs on patients' quality of life. Resultingly, the model could not evaluate patients' utility related to treatment with or without intrauterine spacers and instead focused on costs and events avoided.

CONCLUSION

This analysis robustly demonstrated that intrauterine spacers would be cost-saving to healthcare payers, including both per-patient and per-plan member, through a reduction in IUAs and improvements to patients' pregnancy-related outcomes.

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.

MenSCs Transplantation Improve the Viability of Injured Endometrial Cells Through Activating PI3K/Akt Pathway

Endometrial injury is one of the leading causes of female infertility and is caused by intrauterine surgery, endometrial infection, repeated abortion, or genital tuberculosis. Currently, there is little effective treatment to restore the fertility of patients with severe intrauterine adhesions and thin endometrium. Recent studies have confirmed the promising therapeutic effects of mesenchymal stem cell transplantation on various diseases with definite tissue injury. The aim of this study is to investigate the improvements of menstrual blood-derived endometrial stem cells (MenSCs) transplantation on functional restoration in the endometrium of mouse model. Therefore, ethanol-induced endometrial injury mouse models were randomly divided into two groups: the PBS-treated group, and the MenSCs-treated group. As expected, the endometrial thickness and gland number in the endometrium of MenSCs-treated mice were significantly improved compared to those of PBS-treated mice (P < 0.05), and fibrosis levels were significantly reduced (P < 0.05). Subsequent results revealed that MenSCs treatment significantly promoted angiogenesis in the injured endometrium. Simultaneously, MenSCs enhance the proliferation and antiapoptotic capacity of endometrial cells, which is likely contributed by activating the PI3K/Akt signaling pathway. Further tests also confirmed the chemotaxis of GFP-labeled MenSCs towards the injured uterus. Consequently, MenSCs treatment significantly improved the pregnant mice and the number of embryos in pregnant mice. This study confirmed the superior improvements of MenSCs transplantation on the injured endometrium and uncovered the potential therapeutic mechanism, which provides a promising alternative for patients with serious endometrial injury.

Chitosan combined with intrauterine device prevents intrauterine adhesions after hysteroscopic adhesiolysis: A target trial emulation study

AIM

To compare the efficacy of chitosan and intrauterine device (IUD) combination with an IUD alone in patients with intrauterine adhesions (IUAs) who underwent hysteroscopic adhesiolysis.

METHODS

This retrospective study assessed 303 patients with moderate-to-severe IUA (American Fertility Society [AFS] score ≥5) who underwent hysteroscopic adhesiolysis between January 2018 and December 2020. Using observational data under a cohort design, we emulated a target trial with two treatment arms: chitosan plus IUD and IUD alone groups. Second-look hysteroscopy was performed in all patients 3 months after the initial hysteroscopy. The primary outcome was improved adhesion assessed using the AFS scoring system.

RESULTS

The baseline characteristics were balanced between the two groups. The second hysteroscopy revealed significantly better AFS scores in group A than in group B (values: 3 [1-4] vs. 4 [2-6], p < 0.001; change: 63% [50%-80%] vs. 44% [33%-67%], p < 0.001, respectively). Significantly better menstruation conditions (improved rate: 66% vs. 49%, p = 0.004) and endometrial thickness (mean: 7.0 mm vs. 6.0 mm, p < 0.001) were also observed in group A than in group B. Moreover, group A showed a significantly higher 1-year clinical pregnancy rate (40% vs. 28%, p = 0.037) and better quality of life (p < 0.001) than group B.

CONCLUSIONS

Chitosan and IUD combination showed better efficacy in reducing adhesions and improving clinical outcomes in patients with moderate-to-severe IUA after hysteroscopic adhesiolysis.

Maternal risk factors associated with term low birth weight in India: A review

Low birth weight is one of the leading factors for infant morbidity and mortality. To a large extent affect, various maternal risk factors are associated with pregnancy outcomes by increasing odds of delivering an infant with low birth weight. Despite this association, understanding the maternal risk factors affecting term low birth weight has been a challenging task. To date, limited studies have been conducted in India that exert independent magnitude of these effects on term low birth weight. The aim of this review is to examine the current knowledge of maternal risk factors that contribute to term low birth weight in the Indian population. In order to identify the potentially relevant articles, an extensive literature search was conducted using PubMed, Goggle Scholar and IndMed databases (1993 – Dec 2020). Our results indi­cate that maternal age, educational status, socio-economic status, ethnicity, parity, pre-pregnancy weight, maternal stature, maternal body mass index, obstetric history, maternal anaemia, gestational weight gain, short pregnancy outcome, hypertension during pregnancy, infection, antepartum haemorrhage, tobacco consumption, maternal occupation, maternal psychological stress, alcohol consumption, antenatal care and mid-upper arm circumference have all independent effects on term low birth weight in the Indian pop­ulation. Further, we argue that exploration for various other dimensions of maternal factors and underlying pathways can be useful for a better understanding of how it exerts independent association on term low birth weight in the Indian sub-continent.

Animal models in intrauterine adhesion research

Intrauterine adhesion (IUA) is a gynaecological disease caused by uterine cavity surgeries and infections that leads to partial or total occlusion of the uterine cavity. However, the underlying mechanism(s) and progression of the disease have not yet been identified. IUA has a high recurrence rate and poor prognosis, and effective drugs to prevent adhesion are lacking. Therefore, establishing an effective animal model of IUA is of great significance for revealing the pathogenesis of IUA and the mechanism(s) governing drug effects. Rats, mice, rabbits, and other animals are currently used to establish intrauterine adhesion models. The IUA induction methods include chemical, thermal, or mechanical damage and mechanical damage combined with an infective method. We analysed the advantages and disadvantages of various models and their clinical simulations in order to provide a precise animal model for exploring the pathogenesis, treatment strategies, and prevention of IUA.

Recent progress of Bioinspired Hydrogel-based delivery system for endometrial repair

Endometrial injury is the main fact leading to infertility. Current treatments of endometrial injury present many problems, such as unable to achieve desired effects due to low retention and the inherent potential risk of injury. Besides, it is important to the development of bioinspired material that can mimic the natural tissue and possess native tissue topography. Hydrogel is a kind of bioinspired superhydrophilic materials with unique characteristics, such as excellent biocompatibility, biodegradability, porosity, swelling, and cross-linkage. These unique physiochemical properties of bioinspired hydrogels enable their promising application as novel delivery platform and alternative therapies for endometrial injury. In this mini review, we summarize the recent advances in bioinispred hydrogel-based delivery system for endometrial repair, including as a post-operative physical barrier and therapeutic delivery system. In addition, present status, limitations, and future perspectives are also discussed.

Association of Intrauterine Microbes with Endometrial Factors in Intrauterine Adhesion Formation and after Medicine Treatment

Intrauterine adhesions (IUAs) have caused serious harm to women’s reproductive health. Although emerging evidence has linked intrauterine microbiome to gynecological diseases, the association of intrauterine microbiome with IUA, remains unknown. We performed metagenome-wide association, metabolomics, and transcriptomics studies on IUA and non-IUA uteri of adult rats to identify IUA-associated microbial species, which affected uterine metabolites and endometrial transcriptions. A rat model was used with one side of the duplex uterus undergoing IUA and the other remaining as a non-IUA control. Both 16S rRNA sequencing and metagenome-wide association analysis revealed that instead of Mycoplasmopsis specie in genital tract, murine lung pathogen Mycoplasmopsispulmonis markedly increased in IUA samples and displayed a distinct positive interaction with the host immune system. Moreover, most of the IUA-enriched 58 metabolites positively correlate with M.pulmonis, which inversely correlates with a mitotic progression inhibitor named 3-hydroxycapric acid. A comparison of metabolic profiles of intrauterine flushing fluids from human patients with IUA, endometritis, and fallopian tube obstruction suggested that rat IUA shared much similarity to human IUA. The endometrial gene Tenascin-N, which is responsible for extracellular matrix of wounds, was highly up-regulated, while the key genes encoding parvalbumin, trophectoderm Dkkl1 and telomerase involved in leydig cells, trophectoderm cells, activated T cells and monocytes were dramatically down-regulated in rat IUA endometria. Treatment for rat IUA with estrogen (E2), oxytetracycline (OTC), and a traditional Chinese patent medicine GongXueNing (GXN) did not reduce the incidence of IUA, though inflammatory factor IL-6 was dramatically down-regulated (96–86%) with all three. Instead, in both the E2 and OTC treated groups, IUA became worse with a highly up-regulated B cell receptor signaling pathway, which may be associated with the significantly increased proportions of Ulvibacter or Staphylococcus. Our results suggest an association between intrauterine microbiota alterations, certain uterine metabolites, characteristic changes in endometrial transcription, and IUA and the possibility to intervene in IUA formation by targeting the causal factors, microbial infection, and Tenascin-like proteins.

Genetically engineered FGF1-sericin hydrogel material treats intrauterine adhesion and restores fertility in rat

Endometrial injury can cause intrauterine adhesions (IUA) and induce the formation of endometrial fibrosis, leading to infertility and miscarriage. At present, there is no effective treatment method for severe IUA and uterine basal injury with adhesion area larger than 1/3 of the uterus. In this study, we prepared FGF1 silk sericin hydrogel material (FGF1-SS hydrogel) to treat endometrial injury and prevent endometrial fibrosis. Compared with the silk sericin hydrogel material (WT-SS hydrogel), FGF1-SS hydrogel significantly promotes the cell migration and infiltration ability of endometrial stromal cells (ESCs). More importantly, FGF1-SS hydrogel can release FGF1 stably for a long time and inhibit The ESCs injury model forms fibrosis through the TGF-β/Smad pathway. In the IUA rat model, FGF1-SS hydrogel treatment effectively restored the number of uterine glands and uterine wall thickness in rats, with a fertility rate of 65.1 ± 6.4%. The results show that FGF1-SS hydrogel is expected to be a candidate to prevent IUA.

Reproductive outcomes and reproductive tract microbiota shift in women with moderate-to-severe intrauterine adhesions following 30-day post-hysteroscopic placement of balloon stents or intrauterine contraceptive devices: A randomized controlled trial

BACKGROUND

Intrauterine adhesions (IUA) develop in up to 20% of women with a history of abortion. After hysteroscopic adhesiolysis, balloon stents are usually placed for seven days to prevent recurrence. The efficacy of prolonged use (30 days) of balloon stents has not been determined.

METHODS

The trial was conducted from June 2019 to March 2021. Ninety-one patients who underwent hysteroscopic adhesiolysis for moderate or severe IUA were randomized to receive a 30-day placement of a balloon stent (n = 44) or an intrauterine device (IUD) (n = 47). The primary outcomes were the ongoing pregnancy and miscarriage rates assessed at 15-19 months. The secondary outcomes were the recurrence of IUA and the American Fertility Society (AFS) intrauterine adhesion scores at the first and second hysteroscopies, the diagnosis of new chronic endometritis at the second-look hysteroscopy, and the vaginal/uterine microbiome assessed using 16S rRNA sequencing. The trial was registered at Chinese Clinical Trial Registry (ChiCTR1900023306).

FINDINGS

The ongoing pregnancy rates (balloon 56·4% versus IUD 57·1%) and miscarriage rates (balloon 10·3% versus IUD 22·9%) were not significantly different between the groups. No differences in the recurrence of IUA, reduction of AFS scores, or new endometritis rates were detected. The bacterial load in the uterus and vagina increased in the IUD group but not in the balloon group.

INTERPRETATION

Balloon placement has a similar effect on ongoing pregnancy rates as intrauterine device (IUD) placement. Patients who underwent balloon placement had a lower miscarriage rate, although the difference was not significant. There were no differences in the recurrence rate of IUA, reduction of American Fertility Society scores, or rate of new chronic endometritis. The balloon stent has less effects on the uterine microbiota.

FUNDING

National Natural Science Foundation of China (81802593).

ADSC Exosomes Mediate lncRNA-MIAT Alleviation of Endometrial Fibrosis by Regulating miR-150-5p

Background

Secondary infertility remains a major complication of endometrial fibrosis in women. The use of exosomes from adipose-derived mesenchymal stem cells (ADSCs) has shown promising results for the treatment of endometrial fibrosis. However, the mechanisms of action of ADSC-exosome (ADSC-Exo) therapy remain unclear.

Materials and Methods

An endometrial fibrosis model was established in mice treated with alcohol and endometrial epithelial cells (ESCs) treated with TGF-β1. ADSCs were isolated from Sprague Dawley (SD) rats, and exosomes were isolated from ADSCs using ExoQuick reagent. Exosomes were identified by transmission electron microscopy (TEM), NanoSight, and Western blot analysis. The expression level of lncRNA-MIAT was detected by qPCR analysis. Western blot analysis was carried out to determine the protein levels of fibrosis markers (TGFβR1, α-SMA, and CK19). A dual-luciferase reporter gene assay was used to verify the relationship between target genes. The endometrial tissues of the endometrial fibrosis model were stained with HE and Masson’s trichrome.

Results

ADSCs and ADSC-Exos were successfully isolated, and the expression level of lncRNA-MIAT was significantly down-regulated in endometrial tissue and the TGF-β1-induced ESC injury model, whereas ADSC-Exos increased the expression of lncRNA-MIAT in the TGF-β1-induced ESC model. Functionally, ADSC-Exo treatment repressed endometrial fibrosis in vivo and in vitro by decreasing the expression of hepatic fibrosis markers (α-SMA and TGFβR1) and increasing the expression of CK19. Moreover, miR-150-5p expression was repressed by lncRNA-MIAT in the TGF-β1-induced ESC injury model. The miR-150-5p mimic promoted TGF-β1-induced ESC fibrosis.

Conclusion

ADSC-Exos mediate lncRNA-MIAT alleviation of endometrial fibrosis by regulating miR-150-5p, which suggests that lncRNA-MIAT from ADSC-Exos may be a viable treatment for endometrial fibrosis.

Reproductive outcomes in women with mild intrauterine adhesions; a systematic review and meta-analysis

BACKGROUND

Moderate to severe intrauterine adhesions (IUAs) may greatly impact fertility, predisposing to pregnancy and obstetric complications. The impact of mild IUAs on reproductive performance remains unclear. A systematic review and meta-analysis was performed to examine the long-term reproductive outcomes in women with hysteroscopic identified and treated mild IUAs mild intrauterine adhesions (IUAs).

METHODS

An electronic literature search was conducted using MEDLINE and EMBASE from inception to June 2019. All prospective cohort, cross-sectional studies or randomized controlled trials Clinical trials in which reproductive outcomes of women with mild IUAs, were reported were included.

RESULTS

Five studies, reporting on reproductive outcomes of 229 women with hysteroscopic identified and treated mild IUAs, were included. The pregnancy rate was 62.3% (142 of 228; 95% CI: 0.55-0.72, I² 25%, p = .21) and in 86.6% (123 of 142) a live birth was encountered (95% CI: 0.71-0.97) with 83.1% (108 out of 130) term deliveries (95% CI: 0.53-0.95). A miscarriage was reported in 10% (13 of 130; 95% CI: 0.02-0.26). Due to the lack of a control group, reproductive outcomes were compared to a general population. Pregnancy and live birth rates were significantly lower in women with identified and treated mild IUAs, 90% versus 62.3% and respectively 99.5% versus 86.6%. The miscarriage rate was similar. Data on obstetric and neonatal outcomes are lacking.

CONCLUSIONS

Women with hysteroscopic identified and treated mild IUAs seem to have lower pregnancy and live birth rate compared to the general population. Future studies consisting of a large cohort of women with hysteroscopic identified and treated IUAs with structural follow-up and a control group are needed to confirm our findings.

[Treatment of synechiae related to infertility]

Synechiae are intrauterine adhesions that affect the fertility of women. They are most often of post-traumatic origin. The management of pregnancy abortions in the first trimester and post-delivery retention are the main contributing factors. Synechiae is responsible for cycle disorders and repeated pregnancy loss. Hysteroscopy is the reference method for its diagnosis and treatment. The surgical objective is the restoration of a normal sized cavity and a functional endometrium to allow fertilization and implantation. The use of small diameter (5mm) hysteroscopes and no energy or bipolar energy instruments are recommended. Echo guidance facilitates the treatment of severe synechiae and limits the risk of intraoperative perforation. The main risk of treatment is recurrence, particularly in severe cases where multiple operating times are sometimes necessary. An office hysteroscopy at 6 weeks is recommended to identify and treat these recurrences. Different physical, molecular or cellular methods are studied as primary and secondary prevention of postoperative synechiae. The objective of this review is to provide an update on the treatment of synechiae in the context of infertility.

A Pilot Study of Guided Conservative Hysteroscopic Evacuation of Early Miscarriage

STUDY OBJECTIVE

To evaluate initial feasibility and experience with guided hysteroscopic morcellation for uterine evacuation of early miscarriage.

DESIGN

A prospective pilot study of 10 cases.

SETTING

A tertiary university hospital in Israel.

PATIENTS

Women with confirmed early miscarriage at a gestational age of below 10 weeks from the last menstrual period.

INTERVENTIONS

From May 2020 to October 2020, the hysteroscopic TruClear tissue removal system (Medtronic, Minneapolis, MN) was used for evacuation of early miscarriage in 10 women. The procedures were recorded.

MEASUREMENTS AND MAIN RESULTS

Data including the length of the procedure, visibility, complete evacuation, bleeding, complications, and follow-up ultrasonography (US) were recorded. The mean duration of the procedure was 24 minutes. Complete evacuation was recorded in all cases. No adverse events were recorded in any of the 10 procedures. Normal uterine cavity without evidence of retained products of conception was documented in follow-up evaluation by US in all cases. Four patients underwent a follow-up office hysteroscopy that demonstrated a normal cavity without evidence of adhesions. In 4 cases (40%), an additional suction curettage was performed immediately after the hysteroscopic procedure owing to obscured visibility or an abnormal US scan at the end of the procedure. However, retained products of conception were found in only 1 of these 4 suction specimens (25%).

CONCLUSION

Hysteroscopic morcellation under vision seems to be a safe and feasible technique for management of early missed abortion. This method may have potential as an innovative treatment of miscarriage in selected cases. Further studies are needed to refine the indications and the surgical technique.

Recent developments in bio-scaffold materials as delivery strategies for therapeutics for endometrium regeneration

Intrauterine adhesions (IUAs) refer to the repair disorder after endometrial injury and may lead to uterine infertility, recurrent miscarriage, abnormal menstrual bleeding, and other obstetric complications. It is a pressing public health issue among women of childbearing age. Presently, there are limited clinical treatments for IUA, and there is no sufficient evidence that these treatment modalities can effectively promote regeneration after severe endometrial injury or improve pregnancy outcome. The inhibitory pathological micro-environment is the main factor hindering the repair of endometrial damaged tissues. To address this, tissue engineering and regenerative medicine have been achieving promising developments. Particularly, biomaterials have been used to load stem cells or therapeutic factors or construct an in situ delivery system as a treatment strategy for endometrial injury repair. This article comprehensively discusses the characteristics of various bio-scaffold materials and their application as stem cell or therapeutic factor delivery systems constructed for uterine tissue regeneration.

Identifying the risk factors and incidence of Asherman Syndrome in women with post-abortion uterine curettage

AIM

To evaluate the risk factors and incidence of Asherman Syndrome in women with post-abortion uterine evacuation and curettage.

METHODS

A total of 2546 patients who had surgical abortion (uterine evacuation and curettage) before the 20th gestational week with indications of missed abortion, anembryonic pregnancy, incomplete abortion, and elective curettage in a tertiary antenatal care center were recruited. The patients were called and surveyed for their symptoms; including infertility, oligo-amenorrhea and recurrent pregnancy loss, preterm birth and intrauterine growth retardation and abnormal placentation as criteria of Asherman Syndrome. Diagnostic (office) hysteroscopy was performed for 177 who had one of those complaints.

RESULTS

The incidence of Asherman Syndrome was 1.6% (n = 43/2546). History of ≥3 abortions was the main factor that increased the risk of Asherman Syndrome for by 4.6 times. Use of vacuum aspiration or sharp curettage, premedication for cervical priming, and having a pregnancy >10th gestational weeks were not risk factors for Asherman Syndrome.

CONCLUSION

When the diagnosis was based on presence of symptoms who underwent uterine instrumentation, the incidence of Asherman Syndrome was found to be 1.6%. Repeated abortions were the main risk factor for Asherman Syndrome and avoiding from repeated uterine instrumentations may have a role in prevention.

Patient-reported menstrual and obstetric outcomes following hysteroscopic adhesiolysis for Asherman syndrome

Objective

Review the menstrual and obstetric outcomes among Asherman syndrome patients when stratified by disease severity.

Design

Retrospective cohort study.

Setting

A community teaching hospital affiliated with a large academic medical center.

Patients

A total of 355 Asherman syndrome patients stratified by March classification who underwent hysteroscopic adhesiolysis.

Interventions

Telephone survey, analyzed with multivariable analysis.

Main Outcome Measures

Return of menstruation. Pregnancy, miscarriage, and live birth rate.

Results

A total of 355 patients underwent hysteroscopic adhesiolysis. Of these, 150 (42.3%) patients completed the telephone survey with a mean follow-up of 2.21 years. Additionally, 40.7% had mild, 52.7% had moderate, and 6.6% had severe disease. Furthermore, 25.3% of patients reported amenorrhea at presentation, with mild disease patients having the highest rate of returning menstruation (93.8%) following treatment. The cumulative pregnancy rate was 81.9%, and the cumulative live birth rate was 51.2%, with no statistical differences identified by the classification group.

Conclusion

Asherman syndrome disease severity predicted returning menstruation but not pregnancy or live birth rate.

Conservatively treated endometrial intraepithelial neoplasia/cancer: Risk of intrauterine synechiae

INTRODUCTION

To determine whether progestin type or number of dilation and curettage procedures (D&Cs) were associated with intrauterine synechiae (IS) or pregnancy outcomes in patients conservatively treated for endometrial intraepithelial neoplasia (EIN) or endometrial cancer (EC).

MATERIALS AND METHODS

We evaluated patients conservatively treated for EIN or EC from 2000 to 2017 at an academic center. IS were identified hysteroscopically. We calculated proportions for categorical variables and tested associations between D&C number, progestin, and pregnancy outcomes using Pearson chi-squared and Fisher's exact tests. A post-hoc power analysis indicated sufficient power to detect livebirth.

RESULTS

We analyzed 54 patients, 15 with EIN (28 %) and 39 with EC (72 %), with a mean age of 34 ± 1.2 years. Progestin treatment types included megestrol acetate (MA) (n = 24), MA with levonorgestrel intrauterine device (LngIUD) (n = 10), MA followed by LngIUD (n = 3), and LngIUD alone (n = 6). Mean number of D&Cs was 3.9 ± 0.9. Overall, 53 subjects underwent hysteroscopy; 10 (19 %) had IS. When D&Cs were grouped into 0-2, 3-4 and ≥5, each increase in D&C group had a 2.9 higher odds of IS (OR: 2.91, p = 0.04, CI: 1.05-10.02). LngIUD was associated with a nonsignificant 46 % decrease in the odds of IS (OR: 0.54, p = 0.66, CI: 0.08-2.87). Twenty-two women attempted pregnancy; 14 women achieved a total of 20 pregnancies and 9 women had total of 15 livebirths (41 % livebirth rate). The number of D&Cs and progestin treatment type were not associated with pregnancy outcomes.

DISCUSSION

Among 54 patients conservatively treated for EC/EIN, nearly 20 % developed IS. However, hysteroscopic and/or fertility treatments may improve pregnancy outcomes.

Mini-Review of the New Therapeutic Possibilities in Asherman Syndrome-Where Are We after One Hundred and Twenty-Six Years?

Asherman syndrome is a multifaceted condition describing the partial or complete removal of the uterine cavity and/or cervical canal. It is a highly debatable topic because of its pronounced influence on both reproductive outcomes and gynaecologic symptoms. The latest reports demonstrated that trauma to the endometrium is the main cause of intrauterine adhesion formation. Left untreated, such adhesions gradually lead to a range of repercussions ranging from mild to severe. Considering the lack of non-invasive approaches, the advent of hysteroscopy has revolutionized the entire field, being otherwise considered the most efficient tool offering new directions and amplifying the chances of treating the Asherman syndrome.

Estrogen attenuates TGF-β1-induced EMT in intrauterine adhesion by activating Wnt/β-catenin signaling pathway

Although estrogen has crucial functions for endometrium growth, the specific dose and underlying molecular mechanism in intrauterine adhesion (IUA) remain unclear. In this study, we aimed to investigate the effects of estrogen on epithelial-mesenchymal transition (EMT) in normal and fibrotic endometrium, and the role of estrogen and Wnt/β-catenin signaling in the formation of endometrial fibrosis. CCK-8 and immunofluorescence assay were performed to access the proliferation of different concentrations of estrogen on normal human endometrial epithelial cells (hEECs). qRT-PCR and western blot assay were utilized to explore the effect of estrogen on EMT in normal and fibrotic endometrium, and main components of Wnt/β-catenin signaling pathway in vitro. Hematoxylin and eosin and Masson staining were used to evaluate the effect of estrogen on endometrial morphology and fibrosis in vivo. Our results indicated that the proliferation of normal hEECs was inhibited by estrogen at a concentration of 30 nM accompanied by upregulation of mesenchymal markers and downregulation of epithelial markers. Interestingly, in the model of transforming growth factor β1 (TGF-β1)-induced endometrial fibrosis, the same concentration of estrogen inhibited the process of EMT, which might be partially mediated by regulation of the Wnt/β-catenin pathway. In addition, relatively high doses of estrogen efficiently increased the number of endometrial glands and reduced the area of fibrosis as determined by the reduction of EMT in IUA animal models. Taken together, our results demonstrated that an appropriate concentration of estrogen may prevent the occurrence and development of IUA by inhibiting the TGF-β1-induced EMT and activating the Wnt/β-catenin pathway.

A prospective randomized controlled trial comparing two different treatments of intrauterine adhesions

RESEARCH QUESTION

Intrauterine adhesions (IUA) are primarily caused by trauma to the endometrium, and hysteroscopy is presently the main treatment for IUA. However, high rates of post-operative adhesion re-formation remain a problem. In this study, the combination of an intrauterine device (IUD) with a Foley catheter and the balloon uterine stent were investigated to evaluate their efficacy in preventing adhesion re-formation and the subsequent reproductive outcomes in patients with moderate to severe adhesions.

DESIGN

A prospective randomized controlled study was conducted in a university-affiliated hospital. A total of 171 women with Asherman's syndrome were initially recruited between August 2016 and December 2017 and were randomized to undergo either balloon uterine stent insertion or placement of a contraceptive IUD plus a Foley catheter after hysteroscopic adhesiolysis. Reduction of adhesion scores, incidence of adhesion re-formation, changes in menstrual flow and reproductive outcomes were analysed.

RESULTS

A total of 118 participants were eligible for analysis. The American Fertility Society (AFS) scores were not significantly different between groups before hysteroscopic adhesiolysis. At the second-look hysteroscopy, the AFS scores and adhesion recurrence rates were significantly higher in the balloon uterine stent group compared with the combination group (P < 0.01 and P = 0.024, respectively). There were no statistically significant differences in pregnancy and live birth rates between the two groups.

CONCLUSIONS

The combination of an IUD and a Foley balloon catheter had better efficacy in preventing adhesion re-formation than the balloon uterine stent alone; however, it did not produce better reproductive outcomes.

Foxf2 and Smad6 co-regulation of collagen 5A2 transcription is involved in the pathogenesis of intrauterine adhesion

The replacement of normal endometrial epithelium by fibrotic tissue is the pathological feature of intrauterine adhesion (IUA), which is caused by trauma to the basal layer of the endometrium. COL5A2 is a molecular subtype of collagen V that regulates collagen production in fibrotic tissue. Here, we investigated the roles of Foxf2 and Smad6 in regulating the transcription of COL5A2 and their involvement in the pathogenesis of IUA. Small interference‐mediated Foxf2 (si‐Foxf2) silencing and pcDNA3.1‐mediated Smad6 (pcDNA3.1‐Smad6) up‐regulation were performed in a TGF‐β1‐induced human endometrial stromal cell line (HESC) fibrosis model. Assessment of collagen expression by Western blotting, immunofluorescence and qRT‐PCR showed that COL5A2, COL1A1 and FN were significantly down‐regulated in response to si‐Foxf2 and pcDNA3.1‐Smad6. Transfection of lentivirus vector‐Foxf2 (LV‐Foxf2) and pcDNA3.1‐Smad6 into HESCs and qRT‐PCR showed that Foxf2 promoted COL5A2 expression and Smad6 inhibited Foxf2‐induced COL5A2 expression. Co‐immunoprecipitation, chromatin immunoprecipitation and dual‐luciferase reporter assays to detect the interaction between Foxf2 and Smad6 and their role in COL5A2 transcription showed that Foxf2 interacted with Smad6 and bond the same promoter region of COL5A2. In a rat IUA model, injection of ADV2‐Foxf2‐1810 and ADV4‐Smad6 into the uterine wall showed that Foxf2 down‐regulation and Smad6 up‐regulation decreased fibrosis and the expression of COL5A2 and COL1A1, as detected by haematoxylin/eosin, Masson trichrome staining and immunohistochemistry. Taken together, these results suggested that Foxf2 interacted with Smad6 and co‐regulated COL5A2 transcription in the pathogenesis of IUA, whereas they played opposite roles in fibrosis.

Establishment of an animal model of intrauterine adhesions after surgical abortion and curettage in pregnant rats

Background

Intrauterine adhesion (IUA), also referred to as Asherman syndrome, is a complication with partial or complete adhesion of the uterine cavity due to fibrotic proliferation after endometrial and uterine wall injury of the newly pregnant uterus. Currently, all IUA research models are based on non-pregnant animals which are ill-suited in mimicking its pathogenesis. This study aimed to establish an animal IUA model caused by surgical abortion and curettage in pregnant rats that is more in line with clinical etiology, and to provide a more ideal animal model for further exploration of the pathogenesis and treatment for IUA.

Methods

Fifteen, 13-to-15-day pregnant Sprague-Dawley (SD) rats aged 10 weeks were selected. After incising and removing the embryos, we randomly selected one side of the uterine cavity as the study group (n=15) and scraped it with a curette; the contralateral side of the uterine cavity that underwent no special procedures was used for inclusion in the control group (n=15). Five rats were euthanized and dissected on the 3rd, 7th, and 14th day after surgery respectively. The changes in tissue morphology, the number of endometrial glands, the ratio of endometrial fibrotic area, and the expression level of the transforming growth factor beta (TGF-β) in the endometrium were compared between the 2 groups.

Results

The endometrial granular cell number in the study group on the 7th and 14th day postoperatively was 3.87±0.72 & 2.59±0.90 in each visual field (×100) respectively, which was significantly lower than that of the control group (6.48±0.96 & 7.53±1.10; P<0.05). The ratio of the endometrial stromal fibrotic area in the study group was significantly higher than that of the control group post-operatively on the 3rd day (0.0974±0.0430 vs. 0.0584±0.05110), 7th day (0.1551±0.0348 vs. 0.0328±0.0152), and 14th day (0.1518±0.0477 vs. 0.0311±0.0128) (P<0.05). The endometrial TGF-β expression in the study group was positive on the 14th day postoperatively while weakly expressed in the control group, and the integrated optical density (IOD) value (5,608.8±2,887.3) was higher than that of the control group (388.3±98.6) (P<0.05). The endometrial TGF-β expression in the study group and control group was relatively weak on the 3rd and 7th day after surgery, and there was no significant difference when compared with that of the control group (P>0.05).

Conclusions

The establishment of an animal model of IUA after surgical abortion and curettage in pregnant rats was successful and is thus feasible for further studies; the model may be a more effective mimic for the generation of human IUA.

A Network Meta-Analysis of Efficacy of Different Interventions in the Prevention of Postoperative Intrauterine Adhesions

This network meta‐analysis was conducted to compare the efficacy of six interventions, including anti‐blocking agents, intrauterine contraceptive devices (IUDs), estrogens, intrauterine balloon, Foley catheter, and amnion graft for the prevention of intrauterine adhesions (IUAs). We searched PubMed, Embase, and Cochrane Library from inception to December 2016. Cohort studies meeting these six interventions in the prevention of IUAs were included. The combination of direct and indirect evidence was conducted to assess the odds ratio (OR) or weighted mean differences and surface under the cumulative ranking curves of the six interventions in the prevention of postoperative IUAs. Finally, 12 eligible cohort studies were included in this network meta‐analysis. The results of this network meta‐analysis demonstrated that during 1 to 2 months after operation, compared with the surgical group, anti‐blocking agent, and estrogens presented with relatively low ratios of postoperative IUAs (OR = 0.30 95% confidence interval (CI) = 0.10–0.67; OR = 0.12, 95% CI = 0.01–0.78, respectively). Compared with IUDs, estrogens exerted comparatively low ratio of postoperative IUAs (OR = 0.10, 95% CI = 0.01–0.90), which indicated that anti‐blocking agent and estrogens had relatively better prevention efficacy. The cluster analysis showed that estrogens had relatively better efficacy in the prevention postoperative IUAs. Overall, our findings support that estrogens had relatively better efficacy in the prevention of postoperative IUAs.

Effects of uterus derived mesenchymal stem cells and their exosomes on asherman's syndrome

Asherman's syndrome has become a growing problem with the incidence of cesarean and endometrial surgical procedures. A surgical procedure that can damage to the basal layer of the endometrium is formed as intrauterine adhesion and can cause asherman's syndrome. Mesenchymal stem cells (MSCs) are characterized by some characteristics such as non-immunogenic, angiogenic, antifibrotic, antiapoptotic and antiinflammatory properties, also they support tissue repair by secretion of various factors and chemokines in cellular therapy. Exosomes are active paracrine components with a great potential for repairing damaged tissue. Exosomes include many paracrine factors responsible for regeneration and angiogenesis. In this study, 10 newborn Wistar rats were used to obtain MSCs. A total of 24 adult Wistar rats were also used. The rats were divided into 4 groups: untreated control group; asherman control group; asherman + uterine-derived MSCs group; asherman + uterine-derived MSCs-exosomes group. At the end of the experiment, uterine tissues were evaluated by histochemical and immunohistochemical. As a result of MSCs and exosomes treatments, proliferation and vascularization in uterine tissue was increased. It was also shown to reduce fibrosis with masson's trichrome staining. MMP-2 and MMP-9 expression was enhanced by MSC and exosomal therapy; in addition, TIMP-2 expression was decreased. In our study, it was shown that proliferation and vascularization increased and fibrosis decreased in uterus as a result of MSC and exosome treatments. Our results indicate that the exosomal treatment restored the damage of asherman's syndrome at tissue at a shorter time than the MSCs group.

Live birth after hysteroscopy performed inadvertently during early pregnancy: A case report and review of literature

Generally, hysteroscopy is not appropriate for pregnant women without an indication. What if a patient undergoes hysteroscopy accidentally during the early gestational period? We here report a rare case of a woman who continued pregnancy after a diagnostic hysteroscopy was performed in early pregnancy and delivered a healthy baby. The patient had a history of infertility and oligomenorrhea, probably due to a previous induced abortion. A hysteroscopy was performed after the end of her “menstruation” for assessment of her uterine cavity. Early pregnancy, instead of the expected intrauterine adhesions, was suspected, and the procedure was immediately ceased. Subsequent tests confirmed the diagnosis of pregnancy. She had a full-term delivery by elective caesarean section. The success of this case was attributed to the use of vaginoscopic techniques in hysteroscopy and correct judgment and decision-making during the procedure. This case report provides some useful methods and experience that might be helpful when a similar situation occurs in clinical practice.

Intrauterine adhesions following an induced termination of pregnancy: a nationwide cohort study

OBJECTIVE

Intrauterine adhesions (IUAs) are a problematic complication after termination of pregnancy, but their incidence is unknown. Our objective was to assess the incidence of IUAs following induced termination of pregnancy and the risk factors for IUAs.

DESIGN

Retrospective cohort study.

SETTING

A nationwide registry study.

SAMPLE

All women undergoing induced termination of pregnancy (n = 80 015) in Finland between 2000 and 2008.

METHODS

The data were retrieved from the Finnish Abortion Registry and the Hospital Discharge Registry. The diagnosis of IUAs or complications was based on the diagnostic codes (International Statistical Classification of Diseases and Related Health Problems 10th Revision, ICD-10) and operative codes according to the Nordic Medico-Statistical Committee (NOMESCO) Classification of Surgical Procedures (NCSP). IUAs were defined as ICD-10 code N85.6 or operative code LCG02. A subanalysis of IUA cases and five matched controls was performed.

MAIN OUTCOME MEASURES

The incidence of and risk factors for IUAs.

RESULTS

A total of 12 (1.5 per 10 000) IUA diagnoses were identified from 79 960 eligible induced terminations of pregnancy. The rate of IUAs was 1.5 and 2.0 cases per 10 000 terminations of pregnancy following medically and surgically induced termination of pregnancy, respectively (P = 0.19). In a subgroup analysis of IUA cases and five matched controls, surgical treatment of the remaining products of conception following termination of pregnancy significantly increased the risk of IUAs (odds ratio, OR 5.50; 95% confidence interval, 95% CI 1.46-20.79; P = 0.012).

CONCLUSION

IUAs that require further treatment are rare after an induced termination of pregnancy. Surgical evacuation following medical or surgical termination of pregnancy was a risk factor for the diagnosis of IUAs. These results suggest that trauma to a recently pregnant uterus is an important risk factor for IUAs.

TWEETABLE ABSTRACT

IUA is rare after induced termination of pregnancy (iTOP), but surgical evacuation is a risk factor for IUAs.

A comprehensive review of Asherman's syndrome: causes, symptoms and treatment options

PURPOSE OF REVIEW

Intrauterine adhesions, also known as Asherman's syndrome, can have an impact on both reproductive outcomes and gynaecologic symptoms. Understanding the cause of intrauterine adhesions and the common clinical presentation will increase awareness of the condition and guide the patient to appropriate therapy. Surgical management offers favourable fertility outcomes and is often successful in restoring menstruation.

RECENT FINDINGS

Surgical management with hysteroscopic lysis of adhesions is the gold standard for treatment and adopting an office-based approach offers several advantages. Prevention of reformation of adhesions remains challenging and no single method for preventing recurrence has shown superiority. Cell-based therapies using endometrial stem/progenitor cells hold promise for future use in regenerating inadequate endometrium.

SUMMARY

Increased awareness of the symptoms suggestive of intrauterine adhesive disease, as well as recognition of common causes and preceding events, is crucial for early diagnosis, patient counselling and treatment. VIDEO ABSTRACT: http://links.lww.com/COOG/A36.