Definition and Criteria for Diagnosing Cesarean Scar Disorder

The impact of caesarean scar niche on fertility - a systematic review

BACKGROUND

The trend of increasing caesarean section (CS) rates brings up questions related to subfertility. Research regarding the influence of CS on assisted reproduction techniques (ART) is conflicting. A potential mechanism behind CS-induced subfertility is intra uterine fluid resulting from a caesarean scar defect or niche. The vaginal microbiome has been repeatedly connected to negative ART outcomes, but it is unknown if the microbiome is changed in relation to a niche.

METHODS

This systematic review describes literature investigating the effect of a niche on live birth rates after assisted reproduction. Furthermore, studies investigating a difference in microbial composition in subfertile persons with a niche compared to no niche are evaluated. Pubmed, Embase and Web of Science were searched on March 2023 for comparative studies on both study questions. Inclusion criteria were i.e., English language, human-only studies, availability of the full article and presence of comparative pregnancy data on a niche. The quality of the included studies and their risk of bias were assessed using the Newcastle-Ottawa scale for cohort studies. The results were graphically displayed in a forest plot.

RESULTS

Six retrospective cohort studies could be included on fertility outcomes, with a total of 1083 persons with a niche and 3987 without a niche. The overall direction of effect shows a negative impact of a niche on the live birth rate (pooled aOR 0.58, 95% CI 0.48-0.69) with low-grade evidence. Three studies comparing the microbiome between persons with and without a CS could be identified.

CONCLUSION

There is low-grade evidence to conclude that the presence of a niche reduces live birth rates when compared to persons without a niche. The theory that a caesarean has a negative impact on pregnancy outcomes because of dysbiosis promoted by the niche is interesting, but there is no sufficient literature about this.

Diagnosis of abnormal uterine bleeding based on the FIGO classification: A systematic review and expert opinions

AIM

To present evidence- and consensus-based recommendations for the diagnosis abnormal uterine bleeding.

METHODS

A literature search for the diagnosis of abnormal uterine bleeding was systematically conducted in PubMed from its inception to May 2024 to identify meta-analyses, reviews, randomized controlled trials, and clinical trials, followed by an additional systematic search using keywords. Based on this evidence, an expert panel developed background, clinical, and future research questions.

RESULTS

Based on a systematic search and the collected evidence, we developed five background questions, three clinical questions, and one future research question, with recommendations and/or statements. Evidence and recommendations are provided for clinical questions. Additionally, we developed a flowchart for diagnosis showing the steps of the examinations to be performed.

CONCLUSION

The flowchart and nine recommendations/statements specify an efficient diagnostic procedure to differentiate abnormal causative diseases of uterine bleeding optimized for actual Japanese situations.

Factors Associated to the Presence of Isthmocele Diagnosed by Pelvic Ultrasound, Magnetic Resonance Imaging or Diagnostic Hysteroscopy: A Cross-Sectional Study

We aimed to analyze the prevalence of isthmocele and factors associated with its onset within a cohort of women with previous history of cesarean section. A cross-sectional study with 90 women assessed from 2020 to 2022. Isthmocele was a composite variable diagnosed by transvaginal ultrasound (TVUS), magnetic resonance imaging (MRI) and/or diagnostic hysteroscopy (DxHys) and were asked about clinical symptoms, sociodemographic and obstetrical history and quality of life by the WHO-QOL questionnaire. Univariate and multivariate analysis (odds ratio (OR) plus 95% confidence intervals-CI) were performed to seek factors associated with the presence of isthmocele (5% significance level).The prevalence of isthmocele after combining MRI, TVUS and DxHys was 63.3% (n = 57). Women with isthmocele presented a higher body mass index (BMI) measured during delivery (32.70 ± 6.07 vs. 28.28 ± 9.86 kg/m2;p < 0.05) than women without isthmocele. Other sociodemographic variables, obstetrical history and WHO-QOL subdomains did not differ between groups. Within women with isthmocele, the residual myometrial mantle had an average of 4.97 ± 1.57 cm. Uterine volume was higher in the isthmocele group (103.95 vs. 81.34 cm3; p = 0.08), but with no statistical difference. Multivariate analysis (logistic regression) has reported that the factors associated with isthmocele were: higher BMI during delivery (aOR = 1.26[1.07-1.49];p < 0.05); longer interpartum interval (aOR = 1.22[1.03-1.46];p = 0.02) and presence of more than two cesarean sections (aOR = 2.16[1.16-4.01];p = 0.02). We concluded that a high prevalence of isthmocele was found. Women with previous cesarean section, with higher BMI during delivery and longer interdelivery interval were risk factors for the presence of isthmocele.

Structured hysteroscopic examination of uterine niches: a modified Delphi procedure

Background

Uterine niches in the Caesarean section scar are seen in approximately half of women with a history of caesarean delivery. Whilst a structured ultrasound assessment of caesarean defects has been described, there is no consensus on a structured hysteroscopic evaluation.

Objectives

To propose a methodology for a structured hysteroscopic evaluation of uterine niches.

Materials and Methods

We conducted a modified Delphi procedure, including two online rounds and two face-to-face meetings of the members of the ESGE Uterine Niches Working Group. The taskforce members have extensive experience in hysteroscopic niche evaluation. The consensus was predefined as a Rate of Agreement of at least 75%.

Results

Thirteen experts participated in this modified Delphi procedure. There was consensus on the need for a standardised methodology and the hysteroscopic definition of a niche as any indentation in the myometrium at the site of a previous CS. There was consensus that a hysteroscopic evaluation of a niche must be combined with ultrasound to measure the residual myometrial thickness. In addition, it was agreed that niches should be subclassified as 'simple', 'simple with one branch', or 'complex'. There was consensus that the following items should be described during a hysteroscopic niche evaluation: the number of niches, the size in relation to the size of cervical canal, the presence of polyps, crypts, cysts, fibrotic tissue, blood, mucus, placental remnants, a dynamic valve, the appearance of the endometrium, the number of blood vessels and bleeding from blood vessels within the defect.

Conclusion

Using a modified Delphi procedure with international experts, consensus was achieved on the hysteroscopic evaluation and classification of niches in the uterine caesarean section scar.

What is new?

A structured registration form was developed to aid consistency in hysteroscopic niche reporting.

Barbed vs conventional sutures for cesarean uterine scar defects: a randomized clinical trial

BACKGROUND

The role of barbed sutures in preventing myometrial defects and enhancing postpartum outcomes after cesarean section (C-section) is uncertain.

OBJECTIVE

This study compared clinical and ultrasonographic outcomes of uterine scar defects after C-section with barbed and conventional smooth thread sutures.

STUDY DESIGN

This was a multicenter, parallel-group, randomized, controlled clinical trial. Four obstetrics and gynecology departments across three Japanese healthcare regions were included. The participants were women requiring their first cesarean delivery between May 2020 and March 2023. Of the 1211 participants enrolled, 298 underwent C-section and 253 were followed up until July 2023. Participants with singleton pregnancies were randomly assigned (1:1 ratio) to receive either conventional or spiral thread sutures with a double-layer continuous suture. The study period comprised the time of consent to the 6- to 7-month examination. The primary endpoint was the rate of scar niches >2 mm evaluated using transvaginal ultrasonography at 6 to 7 months after surgery. Additional metrics included the total operative time, suture application time, operative blood loss, number of additional sutures required for hemostasis, maternal surgical complications, postoperative infections, surgeon's years of experience, and individual subscale scores.

RESULTS

All data of the 220 participants (barbed suture group: 110; conventional suture group: 110) were available, thus enabling a full analysis set. A comparison of the barbed and conventional suture groups, respectively, revealed the following: niche length, 2.45±1.65 mm (range: 1.0-6.7) vs 3.79±1.84 mm (range: 1.0-11.0) (P<.001); niche depth, 1.78±1.07 mm (range: 1.0-5.7) vs 2.70±1.34 mm (range: 1.0-7.3) (P<.001); residual myometrial thickness (RMT), 8.46±1.74 mm (range: 4.8-13.0) vs 7.07±2.186 mm (range: 2.2-16.2) (P<.001); and niche width, 1.58±2.73 mm (range: 0.0-14.0) vs 2.88±2.36 mm (range: 0.0-11.0) (P<.001), respectively. The barbed suture group exhibited no defects and an RMT <3 mm. Furthermore, the barbed suture group had a lower rate of uterine niches (29.1%; n=32/110) than the conventional suture group (68.2%; n=75/110). Secondary outcomes showed no significant differences in operative times, maternal surgical complications, or postoperative complications.

CONCLUSION

Double-layer barbed sutures during cesarean delivery may prevent C-section scar defects and postoperative complications. El resumen está disponible en Español al final del artículo.

Single-layer vs double-layer uterine closure during cesarean delivery: 3-year follow-up of a randomized controlled trial (2Close study)

BACKGROUND

The rising rate of cesarean deliveries has led to an increased incidence of long long-term complications, including niche formation in the uterine scar. Niche development is associated with various gynecologic complaints and complications in subsequent pregnancies, such as uterine rupture and placenta accreta spectrum disorders. Although uterine closure technique is considered a potential risk factor for niche development, consensus on the optimal technique remains elusive.

OBJECTIVE

We aimed to evaluate the effect of single-layer vs double-layer closure of the uterine incision on live birth rate at a 3-year follow-up with secondary objectives focusing on gynecologic, fertility, and obstetrical outcomes at the same follow-up.

STUDY DESIGN

A multicenter, double-blind, randomized controlled trial was performed at 32 hospitals in the Netherlands. Women ≥18 years old undergoing a first cesarean delivery were randomly assigned (1:1) to receive either single-layer or double-layer closure of the uterine incision. The primary outcome of the long-term follow-up was the live birth rate; with secondary outcomes, including pregnancy rate, the need for fertility treatment, mode of delivery, and obstetrical and gynecologic complications. This trial is registered on the International Clinical Trials Registry Platform www.who.int (NTR5480; trial finished).

RESULTS

Between 2016 and 2018, the 2Close study randomly assigned 2292 women, with 830 of 1144 and 818 of 1148 responding to the 3-year questionnaire in the single-layer and double-layer closure. No differences were observed in live birth rates; also there were no differences in pregnancy rate, need for fertility treatments, mode of delivery, or uterine ruptures in subsequent pregnancies. High rates of gynecologic symptoms, including spotting (30%-32%), dysmenorrhea (47%-49%), and sexual dysfunction (Female Sexual Function Index score, 23) are reported in both groups.

CONCLUSION

The study did not demonstrate the superiority of double-layer closure over single-layer closure in terms of reproductive outcomes after a first cesarean delivery. This challenges the current recommendation favoring double-layer closure, and we propose that surgeons can choose their preferred technique. Furthermore, the high risk of gynecologic symptoms after a cesarean delivery should be discussed with patients.

Contrast Hysterosonographic Evaluation of Niche Prevalence Following a Standardized Suturing Technique for Caesarean Sections

Introduction

After caesarean section a uterine niche can be detected in 42-84% of all women and in 11-45% large defects with a residual myometrium < 2.2 mm occur. If the niche compromises > 50% of myometrial thickness, risk of uterine rupture during birth increases. The suturing technique might contribute substantially on pathogenesis of niches. The objective of this study is to investigate the effect of the suturing technique on niche prevalence by using a standardized two-layer surgical technique.

Methods

Women with one previous caesarean section were examined within 6-23 months after caesarean section using contrast medium-supported transvaginal sonography regarding the prevalence, sonomorphological aspect and clinical symptoms of a uterine niche. The surgical technique used was: dilatation of the cervix, interrupted suture of the first layer (excluding the endometrium), continuous closure of the visceral and parietal peritoneum.

Results

Using native vaginal sonography, no niches were visible in the whole cohort. In three cases, there was a small niche detectable with a depth between 2.3 and 3.9 mm by contrast hysterosonography. Regarding the total myometrial thickness, the niche depth compromised less than 50%. All patients were symptom-free.

Conclusion

In our study population, there were only three cases (9.1%) with a small uterine niche. Residual myometrium and niche percentage on myometrial thickness were excellent in all three cases. Thus, our results show that the uterotomy closure technique used in the study cohort might be superior with respect to the development of uterine niches compared with the expected prevalence.

Emerging data on diagnosis and management of uterine isthmoceles: a rapid review

PURPOSE OF REVIEW

With a rising number of cesarean sections, the prevalence of uterine isthmoceles is increasing. We performed a rapid review to assess the most recent data on the diagnosis and management of uterine isthmoceles over the past 18 months to identify current trends and directions for continued research.

RECENT FINDINGS

A comprehensive search was conducted in PubMed (NLM), Embase (Ovid), CINAHL (EBSCOhost) to find English written articles discussing the diagnosis or management of uterine isthmoceles published in the previous 18 months. Data extraction was performed on one hundred articles that met inclusion criteria.

SUMMARY

This rapid review highlights agreement regarding diagnostic methods, symptoms, and recommended treatment paths for patients with symptomatic uterine niches. However, the diversity in definitions hampers the capacity to formulate detailed conclusions regarding the features of uterine niches and their impact on women's health.

Effectiveness of an articulating laparoscopic needle holder for cesarean scar defect repair

AIM

To evaluate the efficacy of an articulating laparoscopic needle holder in laparoscopic surgery for cesarean scar defect.

METHODS

We performed a retrospective case-control study at the Shiga University of Medical Science. Patients who underwent laparoscopic uterine scar repair were divided into an articulating laparoscopic needle holder (ArtiSential®) group and a rigid needle holder (conventional) group to compare the suture and total operative times. Uterine myometrial suturing involves a double-layer interrupted suture, including a modified Gambee suture for the first layer. We measured the residual myometrial thickness using magnetic resonance imaging preoperatively and at 3 months postoperatively.

RESULTS

Both groups comprised 10 patients each. The time per stitch for the first and second layers was significantly shorter in the ArtiSential group than in the conventional group (median 208 s vs. 403 s, p < 0.0001 and median 17 s vs. 29 s; p < 0.0001, respectively). The total operating time was significantly shorter in the ArtiSential group (mean 188 min vs. 240 min, p = 0.0015). The postoperative residual myometrial thickness (mean 9.1 mm in the ArtiSential group and 9.6 mm in the conventional group) was significantly higher than the preoperative residual myometrial thickness (mean 1.6 mm in the ArtiSential group and 1.6 mm in the conventional group) (p < 0.0001 in both groups).

CONCLUSIONS

An articulating needle holder is useful in laparoscopic surgery for cesarean scar defect, especially when a modified Gambee suture is required.

The association between gynecological complaints and the uterine sonographic features in women with a history of cesarean section

PURPOSE

The aim of this study is to investigate the association between post-cesarean sonographic uterine measures, dysmenorrhea, and bleeding disorders.

METHODS

This is a cross-sectional study where 500 women with a history of only one cesarean section (CS) were recruited. A transvaginal transducer, GE RIC6-12-D was used for the acquisition of volumetric datasets 18 ± 7 months postpartum. Uterine length (UL), cervical length (CL), niche length (L), niche depth (D), niche width (W), fibrosis length (FL), fibrosis depth (FD), residual myometrial thickness (RMT), endometrial thickness (EM), scar to internal os distance (SO), anterior myometrial thickness superior (sAMT) and inferior (iAMT) to the scar, and the posterior myometrial thickness opposite the scar (PMT), superior (sPMT), and inferior to it (iPMT) were measured. Logistic regression with odds ratios (OR), 95% confidence intervals (CI) and ROC curves were utilized.

RESULTS

The proportion of patients with incident post-cesarean bleeding disorders and dysmenorrhoea was 36% (CI 32%, 40%) and 17% (CI 14%, 21%) respectively. Univariate logistic regression showed that only UL was associated with bleeding disorders [OR 1.04 (CI 1.01,10.7) p value 0.005], whereas dysmenorrhea was associated with RMT [OR 0.82 (CI 0.71,0.95) p value 0.008], SO [OR 0.91 (CI 0.86,0.98) p value 0.01], and RMT ratio [OR 0.98 (CI 0.97,0.99) p value 0.03]. Multivariate logistic regression for dysmenorrhoea including SO and RMT remains statistically significant with p values <0.05 and area under the curve of 0.66.

CONCLUSION

There is an association between sonographic appearance of CS scars and dysmenorrhoea. Nevertheless, the association is weak and other biological post-cesarean characteristics should be explored as potential causes.

Early first-trimester transvaginal ultrasound screening for cesarean scar pregnancy in patients with previous cesarean delivery: analysis of the evidence

Obstetric hemorrhage is a leading cause of maternal morbidity and mortality. An important etiology of obstetric hemorrhage is placenta accreta spectrum. In the last 2 decades, there has been increased clinical experience of the devastating effect of undiagnosed, as well as late diagnosed, cases of cesarean scar pregnancy. There is a growing body of evidence suggesting that cesarean scar pregnancy is an early precursor of second- and third-trimester placenta accreta spectrum. As such, cesarean scar pregnancy should be diagnosed in the early first trimester. This early diagnosis could be achieved by introducing regimented sonographic screening in pregnancies of patients with previous cesarean delivery. This opinion article evaluates the scientific and clinical basis of whether cesarean scar pregnancy, with special focus on its early first-trimester discovery, complies with the accepted requirements of a screening test. Each of the 10 classical screening criteria of Wilson and Jungner were systematically applied to evaluate if the criteria were met by cesarean scar pregnancy, to analyze if it is possible and realistic to carry out screening in a population-wide fashion.

A morphological study of symptomatic uterine niche using three-dimensional models from thin-slice magnetic resonance imaging

RESEARCH QUESTION

Is there a correlation between various morphological parameters of the uterine niche and post-menstrual spotting using three-dimensional models from thin-slice (1 mm) magnetic resonance imaging (MRI)?

DESIGN

This study retrospectively identified women diagnosed with a symptomatic niche by thin-slice MRI between December 2019 and December 2021. Univariable and multivariable linear regression models assessed the correlations between morphological parameters and the duration post-menstrual spotting. Morphological differences of the niche formed by one versus two Caesarean sections were analysed by univariable and multivariable logistic analysis.

RESULTS

A total of 205 women diagnosed with symptomatic niche were included in the study. The niche among most women with post-menstrual spotting was ellipsoidal, with width greater than length greater than depth, from which niche volume was estimated based on manual measurements (volume = 0.520 × length × width × depth). Manually calculated niche length (β = 0.257, 95% confidence interval [CI] 0.040-0.473, P = 0.020) and radiomically assessed minor axis length (β = 0.329, 95% CI 0.009-0.795, P = 0.045) both positively correlated with the duration of post-menstrual spotting, whereas the distance between the niche and external os (β = -0.120, 95% CI -0.202 to -0.038, P = 0.004) was inversely correlated. Women with two Cesarean sections reported more days of post-menstrual spotting (8.76 ± 3.54 versus 6.68 ± 3.90 days, P < 0.001) and had increased niche length diameter (adjusted odds ratio [aOR] 1.304, 95% CI 1.190-1.429) and a smaller surface-area-to-volume ratio (aOR 0.296, 95% CI 0.129-0.680).

CONCLUSIONS

Niche-associated post-menstrual spotting correlates with the length diameter of the niche and the distance between the niche and external os. Niches in women after two Caesarean sections tend to be longer in length diameter and more spherical.

Reproductive outcomes after in vitro fertilization in women with cesarean section scar diverticulum: A retrospective study

PURPOSE

Some studies have suggested that cesarean section diverticulum may affect the pregnancy outcomes of assisted reproductive technology through a variety of mechanisms. This study aims to explore whether previous cesarean section and uterine scar diverticulum affect pregnancy outcomes after in vitro fertilization.

METHODS

This retrospective study included 954 infertile women with only one previous delivery who had in vitro fertilization treatment and underwent fresh embryo transplantation for the first time at our center between 2015 and 2019. We first divided the women into two groups by previous vaginal delivery (n = 557) or cesarean section delivery (n = 397), and the latter group included 88 women with cesarean diverticulum and 309 women without cesarean diverticulum. Baseline characteristics were compared and analyzed, and logistic regression analyses were performed to explore the different pregnancy outcomes among the above groups.

RESULTS

Although the live birth rate, clinical pregnancy rate, and mean embryo implantation rate after in vitro fertilization were significantly reduced in patients with previous cesarean section (live birth rate: 26.45% vs. 43.99%, adjusted OR: 0.602, CI: 0.447-0.810; clinical pregnancy rate: 35.26% vs. 49.91%, adjusted OR: 0.724, CI: 0.544-0.962; mean embryo implantation rate: 0.227 ± 0.378 vs. 0.243 ± 0.397, adjusted OR: 0.860, CI: 0.514-1.439), there were no significant differences in pregnancy outcomes between the women with cesarean diverticulum and without cesarean diverticulum (p > 0.05) or between the two groups at different ages. The live birth and clinical pregnancy rates in the women with residual muscle thickness ≤2.2 mm or prolonged menstruation were reduced, but the difference was not statistically significant (p > 0.05).

CONCLUSION

This study showed reduced pregnancy and live birth rates after in vitro fertilization in patients with previous cesarean section, while uterine scarring did not adversely affect pregnancy and delivery outcomes after in vitro fertiliazation.

Cervical Stenosis After Hysteroscopic Surgery for Cesarean Scar Disorder

Cesarean scar disorder (CSDi) is a newly recognized cause of secondary infertility. Laparoscopic or hysteroscopic surgery is generally chosen for the surgical treatment of CSDi, depending on the residual myometrial thickness of the cesarean scar. Previously, hysteroscopic transcervical resection for CSDi (TCR-CSDi) has been reported to be a safe procedure, with no cases of postoperative cervical stenosis. Herein, we report a novel case of cervical stenosis after circumferential hysteroscopic TCR-CSDi of an extensive CSDi lesion. Notably, although no cervical stenosis was observed upon postoperative hysteroscopy one month postoperatively, cervical stenosis developed four months after the surgery; therefore, it is important to avoid circumferential resection and cauterization in patients with CSDi, even when abnormal blood vessels are present. Additionally, it is advisable to check for delayed cervical stenosis at least three weeks before embryo transfer in patients who have undergone TCR-CSDi.

The effect of uterine closure technique on cesarean scar niche development after multiple cesarean deliveries

OBJECTIVES

To use saline infusion sonohysterography (SIS) to evaluate the effect of uterine closure technique on niche formation after multiple cesarean deliveries (CDs).

METHODS

Patients with at least one prior CD were evaluated for niche via SIS. Subgroups of any number repeat CD (>1 prior), lower-order CD (<4 prior), and higher-order CD (≥4 prior) were analyzed, stratifying by hysterotomy closure technique at last cesarean preceding imaging; techniques included Technique A (endometrium-free double-layer closure) and Technique B (single- or double-layer routine endo-myometrial closure). Niche defects were quantified (depth, length, width, and residual myometrial thickness). The primary outcome was clinically significant niche, defined as depth >2 mm. Statistical analysis was performed using chi-square, ANOVA, t-test, Kruskal-Wallis, and multiple logistic regression, with p-values of <0.05 were statistically significant.

RESULTS

A total of 172 post-cesarean SIS studies were reviewed: 105 after repeat CDs, 131 after lower-order CDs, and 41 after higher-order CDs. Technique A was associated with a shorter interval to imaging and more double-layer closures. Technique B was associated with more clinically significant niches across all subgroups, and these niches were significantly longer and deeper when present. Multiple logistic regression demonstrated a 5.6, 8.1, and 11-fold increased adjusted odds of clinically significant niche following Technique B closure in the repeat CD (p<0.01), lower-order CD (p<0.001), and higher-order CD (p=0.04) groups, respectively.

CONCLUSIONS

While multiple CDs are known to increase risk for niche defects and their sequelae, hysterotomy closure technique may help to reduce niche development and severity.

Evaluating resectoscopy and the levonorgestrel intrauterine system for intermenstrual bleeding associated with cesarean scar defects: A retrospective study of treatment outcomes

AIM

To compare and evaluate the efficacy of the levonorgestrel-releasing intrauterine system (LNG-IUD) and resectoscopy remodeling procedure for intermenstrual bleeding associated with previous cesarean delivery scar defect (PCDS).

METHODS

A retrospective comparative study was conducted on patients with PCDS receiving LNG-IUD (levonorgestrel 20 μg/24 h, N = 33) or resectoscopy remodeling (N = 27). Treatment outcomes were compared over 1, 6, and 12 months. Outcomes in patients with a retroverted or large uterus size, defect size, and local vascularization also were evaluated.

RESULTS

At 12 months post-treatment, there were no significant differences between groups in efficacy rate; however, the reduction of intermenstrual bleeding days was higher in the LNG-IUD group than in the resectoscopy group (13.6 vs. 8.5 days, p = 0.015). Within the first year, both groups experienced a reduction in bleeding days, but the decrease was greater in the LNG-IUD group. Individuals exhibiting increased local vascularization at the defect site experienced more favorable outcomes in the LNG-IUD group than the resectoscopy group (p = 0.016), and who responded poorly tended to have a significantly larger uterus in the LNG-IUD group (p = 0.019). No significant differences were observed in treatment outcomes for patients with a retroverted uterus or large defect in either group.

CONCLUSIONS

Our findings support that the LNG-IUD is as effective as resectoscopy in reducing intermenstrual bleeding days associated with PCDS and can be safely applied to patients without recent fertility aspirations. Patients with increased local vascularization observed during hysteroscopy may benefit more from LNG-IUD intervention than resectoscopy.

Influence of Cesarean Section on Postpartum Fertility and Dysmenorrhea: A Retrospective Cohort Study in Japan

Objective

To investigate the association between cesarean section (CS) and postpartum fertility and dysmenorrhea using data from a Japanese insurance registry.

Methods

This retrospective cohort study used a data set of patients registered between 2007 and 2021 in an insurance registry comprising specific employee-based health insurance companies in Japan. Of those data sets, we included data from participants who had their first recorded childbirth between 2014 and 2018. The exclusion criteria were any prior deliveries, dysmenorrhea, or complications that would affect the next pregnancy or postpartum dysmenorrhea since 2007. The occurrence of subsequent childbirth and postpartum dysmenorrhea until 2021 was compared between the CS and vaginal delivery (VD) groups using the log-rank test and Cox proportional hazards model with stratification according to age and age matching.

Results

This study included 25,984 (5,926 after age matching) and 5,926 participants in the VD and CS groups, respectively. After age matching, the rate of subsequent childbirth was 18.3% and 16.3%, and the rate of postpartum dysmenorrhea was 6.5% and 7.8% in the VD and CS groups, respectively. There were fewer subsequent childbirths in the CS group than in the VD group after age matching in the stratified Cox proportional hazards model (hazard ratio [HR] 95% confidence interval [CI]: 0.86 [0.79-0.94]). The CS group had a significantly higher risk of dysmenorrhea (HR [95% CI]: 1.18 [1.03-1.36]).

Conclusions

Although confounding might be existing, our study suggests that CS might be associated with decreased postpartum fertility and increased dysmenorrhea. The medical indications for CS should be carefully determined; post-CS women should be meticulously followed up.

Impact of Caesarean section on pregnancy outcomes in ART after transfer of one or more frozen blastocysts

INTRODUCTION

The prevalence of Caesarean delivery is rising steadily worldwide, and it is important to identify its future impact on fertility. A number of articles have been published on this subject, but the impact of Caesarean section on reproductive outcomes is still under debate, and none of these articles focus exclusively on frozen blastocysts.

OBJECTIVE

The aim of this study was to evaluate the impact of a previous Caesarean delivery compared with a previous vaginal delivery on the chances of a live birth following the transfer of one or more frozen embryos at the blastocyst stage.

METHODS

This was a retrospective, bicentric study at the University Hospitals of Nîmes and Montpellier, conducted between January 1st, 2016 and February 1st, 2021. Three hundred and ninety women with a history of childbirth and a transfer of one or more frozen embryos at blastocyst stage were included in the analysis. The primary outcome was the number of live births. Secondary outcomes were: the rate of positive HCG, miscarriage, ectopic pregnancy and clinical pregnancy, as well as the live birth rate according to the presence or absence of an isthmocele.

RESULTS

Of the 390 patients included, 118 had a previous Caesarean delivery and 272 a vaginal delivery. No statistically significant differences were found for the primary (p = 0.9) or secondary outcomes. A trend towards lower live birth rates was observed in patients with isthmoceles, but this did not reach significance (p>0.9). On the other hand, transfers were more often described as difficult in the Caesarean delivery group (p = 0.011).

CONCLUSION

Our study found no effect of previous Caesarean delivery on the chances of live birth after transferring one or more frozen blastocysts. However, further prospective studies are needed to confirm these results.

Aetiology, risk factors and preventive strategies for niche development: A review

The increase in caesarean sections (CS) has resulted in an increase in women with a uterine niche. The exact aetiology of niche development has yet to be elucidated but is likely multifactorial. This study aimed to give a systematic overview of the available literature on histopathological features, risk factors and results of preventive strategies on niche development to gain more insight into the underlying mechanisms. Based on current published data histopathological findings associated with niche development were necrosis, fibrosis, inflammation, adenomyosis and insufficient approximation. Patient-related risk factors included multiple CS, BMI and smoking. Labour-related factors were CS before onset of labour, extended cervical dilatation, premature rupture of membranes and presenting part of the fetus at CS below the pelvic inlet. Preventive strategies should focus on the optimal level of incision, training of surgeons and full-thickness closure of the myometrium (single or double-layer) using non-locking sutures. Conflicting data exist concerning the effect of endometrial inclusion. Future studies without heterogeneity in population, using standardized performance of the CS after proper training and using standardized niche evaluation with a relevant core outcome set are required to allow meta-analyses and to develop evidence-based preventive strategies. These studies are needed to reduce the prevalence of niches and prevent complications in subsequent pregnancies such as caesarean scar pregnancies.

Cesarean scar disorder: Management and repair

Cesarean scar disorder (CSD) is an entity recently defined as uterine niche with at least one primary or 2 secondary symptoms. CSDs can be visualized by hysterosalpingography, transvaginal sonography, saline infusion sonohysterography, hysteroscopy, and magnetic resonance imaging, but diagnosis should be performed by exams able to measure the residual myometrial thickness (RMT). Although there is a limited number of studies evaluating fertility and reproductive outcomes after different types of surgery, the following consideration should be kept in mind. Asymptomatic women should not be operated with the hope of improving obstetrical outcomes. It is reasonable to consider hormone therapy for CSDs as a symptomatic treatment in women who no longer wish to conceive and have no contraindications. In case of failure of or contraindications to medical treatment, surgery should be offered according to the severity of symptoms, including infertility, the desire or otherwise to preserve the uterus, the size of the CSD, and RMT measurement. Hysteroscopy is considered to be more of a resection than a repair, so women who desire pregnancy should be excluded from this technique in case of RMT <3 mm. In this instance, repair is essential and can only be achieved by a laparoscopic or vaginal approach. The benefit of laparoscopic approach seems to persist after subsequent CS. Women with CSDs need to be given complete information, including available literature, before any treatment decision is made.

The definition, diagnosis, and symptoms of the uterine niche - A systematic review

Of all neonates, 21% are delivered by cesarean section (CS). A long-term maternal complication of an SC is a uterine niche. The aim of this review is to provide an overview of the current literature on imaging techniques and niche-related symptomatology. We performed systematic searches on imaging and niche symptoms. For both searches, 87 new studies were included. Niche evaluation by transvaginal sonography (TVS) or contrast sonohysterography (SHG) proved superior over hysteroscopy or magnetic resonance imaging. Studies that used SHG in a random population identified a niche prevalence of 42%-84%. Niche prevalence differed based on niche definition, symptomatology, and imaging technique. Most studies reported an association with gynecological symptoms, poor reproductive outcomes, obstetrical complications, and reduced quality of life. In conclusion, non-invasive TVS and SHG are the superior imaging modalities to diagnose a niche. Niches are prevalent and strongly associated with gynecological symptoms and poor reproductive outcomes.

Prevalence, definition, and etiology of cesarean scar defect and treatment of cesarean scar disorder: A narrative review

Background

Cesarean scar defects (CSD) are caused by cesarean sections and cause various symptoms. Although there has been no previous consensus on the name of this condition for a long time, it has been named cesarean scar disorder (CSDi).

Methods

This review summarizes the definition, prevalence, and etiology of CSD, as well as the pathophysiology and treatment of CSDi. We focused on surgical therapy and examined the effects and procedures of laparoscopy, hysteroscopy, and transvaginal surgery.

Main findings

The definition of CSD was proposed as an anechoic lesion with a depth of at least 2 mm because of the varied prevalence, owing to the lack of consensus. CSD incidence depends on the number of times, procedure, and situation of cesarean sections. Histopathological findings in CSD are fibrosis and adenomyosis, and chronic inflammation in the uterine and pelvic cavities decreases fertility in women with CSDi. Although the surgical procedures are not standardized, laparoscopic, hysteroscopic, and transvaginal surgeries are effective.

Conclusion

The cause and pathology of CSDi are becoming clear. However, there is variability in the prevalence and treatment strategies. Therefore, it is necessary to conduct further studies using the same definitions.