Clinical Outcomes of Laparoscopic Folding Suture for Cesarean Scar Defect and Its Impact on Pregnancy Outcomes: A Retrospective Study

Abstract

Background

Cesarean scar defect (CSD) is characterized by localized thinning of the myometrium due to defective healing of a previous cesarean section incision. It is frequently associated with abnormal uterine bleeding (AUB) and secondary infertility, and high-quality evidence regarding its surgical management is lacking. As a novel reconstructive technique, the efficacy of laparoscopic CSD folding suture in alleviating AUB and improving fertility outcomes remains to be validated.

Purpose

In the absence of high-quality evidence, this study aimed to provide preliminary evidence on the efficacy of laparoscopic folding suture in relieving AUB-related symptoms (assessed by menstrual duration) and optimizing reproductive outcomes, and to assess its feasibility and safety.

Patients and Methods

This single-centre, retrospective case series included patients who underwent laparoscopic folding suture for CSD at Shandong Provincial Maternal and Child Health Hospital between October 2021 and March 2025. A total of 36 patients were assessed for eligibility; 10 were excluded for the following reasons: lost to follow-up within 3 months postoperatively (n = 3), prior hysteroscopic repair of CSD (n = 2), concurrent endometrial polyps (n = 3), and confirmed tubal factor infertility (n = 2). The remaining 26 women were included in the final analysis. The primary endpoint was change in menstrual duration before and after surgery; secondary endpoints comprised subsequent pregnancy outcomes, change in residual myometrial thickness (RMT), and perioperative adverse events.

Results

Menstrual duration was shortened in 96.2% of patients (25/26), with the median menstrual duration significantly decreasing from 14.5 days (IQR 10.0–15.0) preoperatively to 7.0 days (IQR 6.0–9.0) postoperatively (P < 0.001). Sixteen (61.5%) were actively trying to conceive; during follow-up, 12 of these individuals (75%) achieved pregnancy. Intraoperative blood loss was 30 mL (IQR 20–50). The RMT increased significantly from 1.3 mm (IQR 1.0–1.7) preoperatively to 6.5 mm (IQR 5.0–7.0) postoperatively (median increase 5.2 mm; P < 0.001).

Conclusion

This single-centre retrospective case series suggests that laparoscopic folding suture is a safe and feasible technique for CSD repair, associated with significant improvement in menstrual symptoms and favorable pregnancy outcomes. However, due to the study design, these preliminary findings warrant confirmation in larger, prospective controlled trials.

Introduction

WHO modeling estimates indicate that by 2030 approximately 28.5% of all deliveries worldwide will be accomplished via cesarean section (CS).¹ Cesarean scar defect (CSD) is a long-term sequela of cesarean section that results from impaired healing of the hysterotomy site, leading to focal myometrial thinning and formation of a pouch- or cavity-like defect communicating with the uterine cavity. Transvaginal ultrasonography (TVUS) is currently the primary diagnostic tool for CSD.² The international Niche Working Group defines CSD as a ≥2 mm myometrial indentation at the site of the previous cesarean section detected by TVUS.³ CSD can present with a range of clinically significant symptoms, including abnormal uterine bleeding (AUB) (such as prolonged menstrual duration), chronic pelvic pain, and dyspareunia; in severe cases, it can impair fertility. Post-menstrual spotting is the most frequently reported manifestation. CSD also significantly increases the risk of major obstetric complications, including cesarean scar pregnancy (CSP), placenta accreta spectrum disorders, and uterine rupture.⁴ CSP represents a significant clinical burden, with increasing incidence and high risks of maternal morbidity and mortality, including progression to placenta accreta spectrum and potential need for peripartum hysterectomy.⁵ As the global CS rate continues to rise, the prevalence of CSD has increased in parallel. TVUS studies have identified CSD in approximately 60% of women with a previous cesarean delivery, with nearly 30% of these individuals exhibiting associated clinical symptoms.⁶ CSD significantly impairs quality of life in women, while concurrently generating excess healthcare expenditures and elevating the risk of repeat surgery. Consequently, CSD has emerged as a significant public health concern with considerable socioeconomic implications.

For symptomatic patients with CSD, particularly those presenting with prolonged menstrual duration or secondary infertility, surgical intervention is generally recommended. Current surgical options include hysteroscopic resection, laparoscopic/open excision and primary repair of the defect, transvaginal excision and suture, and laparoscopic folding suture of the defect. However, the optimal surgical modality remains undefined. Residual myometrial thickness (RMT) at the CSD is a pivotal parameter guiding the choice of surgical strategy.⁷ The Scientific Committee of the 2018 Global Congress of Hysteroscopy released a consensus statement on the management of symptomatic CSD, declaring that an RMT < 3.0 mm markedly elevates the risks of uterine perforation and bladder injury during hysteroscopic procedures.⁸ Accordingly, when RMT < 3.0 mm, laparoscopic, open abdominal, or transvaginal route for niche defect should be preferentially considered. Laparoscopic or open “defect resection plus layered myometrial approximation” enables complete excision of fibrotic tissue and restoration of anatomical integrity; however, it entails longer operative time, greater blood loss and a mandatory 18- to 24-month contraceptive interval, leading to suboptimal compliance among women who still desire future fertility. Moreover, the unpredictable healing of the newly created uterine scar leaves a residual risk of subsequent CSD recurrence.⁹ The transvaginal approach, while avoiding abdominal incisions and pneumoperitoneum, is constrained by limited surgical field visualization; operative difficulty rises markedly in the setting of pelvic adhesions or a retroverted uterus, and the learning curve remains steep.

Recently, investigators worldwide have begun to explore the “laparoscopic folding suture” for CSD repair: without resecting the niche defect, the defect base is invaginated and approximated with transverse mattress sutures that collapse the defect, double the myometrial thickness and eliminate the dead space, thereby augmenting uterine wall tension while preserving uterine integrity. Because published experience remains limited, the present pilot study was designed to evaluate the preliminary clinical efficacy and subsequent reproductive outcomes of this novel technique.

Materials and Methods

Study Population

This retrospective study enrolled consecutive patients who underwent laparoscopic folding suture of CSD at Shandong Provincial Maternal and Child Health Hospital between October 2021 and March 2025. Inclusion criteria: (i) TVUS demonstrated an RMT ≤ 3.0 mm; (ii) no prior surgical repair of CSD; (iii) presence of CSD-related symptoms, prolonged menstrual duration with or without secondary infertility. Exclusion criteria: (i) RMT > 3.0 mm; (ii) previous CSD repair of any type (hysteroscopic, transvaginal, laparoscopic, or open); (iii) prolonged menstrual duration attributable to other identifiable causes; (iv) other causes of secondary infertility. A total of 36 patients were assessed for eligibility; 10 were excluded for the following reasons: lost to follow-up within 3 months postoperatively (n = 3), prior hysteroscopic repair of CSD (n = 2), concurrent endometrial polyps (n = 3), and confirmed tubal factor infertility (n = 2). The remaining 26 women were included in the final analysis.

Follow-up data were retrieved from the hospital’s outpatient electronic medical record system. For patients who did not attend scheduled visits, follow-up information was obtained via structured telephone interviews after obtaining verbal consent. All participants underwent standardized preoperative cervical cancer screening, and those with cytological abnormalities were excluded. Postoperative pregnancy was diagnosed by transvaginal ultrasound showing an intrauterine gestational sac with either a yolk sac or embryonic cardiac activity.

This retrospective study was approved by the Ethics Committee of Shandong Provincial Maternal and Child Health Hospital (waiver letter dated November 28, 2020) and was conducted in accordance with the Declaration of Helsinki. The requirement for informed consent was waived due to the retrospective nature of the analysis. To ensure patient privacy, all clinical data were fully anonymized before the analysis, and no additional interventions were performed.

Surgical Methods

The surgical platform consisted of a high-definition laparoscopic system and a 12° rigid hysteroscope with an outer diameter of 9.5 mm (including the operative sheath), both from KARL STORZ, Germany. Distension was achieved with isotonic saline (0.9% NaCl) at 100 mmHg. The video signals were synchronously displayed via the same-brand camera and imaging unit. First, under hysteroscopic guidance, the depth and extent of the CSD were quantified, and the presence of intradefect endometrium, residual hematometra, or endometrial lesions was recorded. Simultaneous hysteroscopic transillumination was employed to enable rapid laparoscopic localization of the thinned myometrial area. Subsequently, the entire defect floor was thoroughly coagulated with a roller-ball electrode. Following the hysteroscopic assessment, laparoscopic pelvic exploration was performed. The vesicouterine peritoneal reflection was incised and the bladder was bluntly mobilized caudally to 2 cm below the inferior margin of the defect, fully exposing the operative field. A transillumination test using the hysteroscope’s cold-light source was performed to confirm the exact location of the CSD. The defect was obliterated with a continuous folding suture using 2–0 barbed suture (approximately 1 cm intervals), approximating its upper and lower rims, after which the myometrium was closed and the serosal surface was reperitonealized. In markedly retroverted uteri, the round ligaments were simultaneously shortened in eight patients to convert the uterus to a horizontal or anteverted position,¹⁰ thereby reducing tension on the scar and the risk of recurrent CSD. Hysteroscopy was reintroduced to confirm that the defect site was virtually flat. A Hegar dilator was kept in the cervical canal throughout the procedure to guide needle direction and prevent inadvertent incorporation of the posterior wall; it was removed after the repair was completed (Figure 1). Myometrial healing was assessed by TVUS at 1 month postoperatively (Figure 2).

Figure 1.

Surgical procedure of laparoscopic folding suture for CSD. (A) Hysteroscopic image of a niche-like defect (arrow) at the isthmus, containing small blood clots and scant endometrial tissue. (B) Roller-ball electrode coagulation of the defect endometrium. (C) Laparoscopic downward mobilization of the bladder. (D) Laparoscopic transillumination test with hysteroscopic light source. (E) The barbed suture achieving continuous full-thickness muscular reefing of the superior and inferior rims of the CSD. (F) Hysteroscopic view of the niche morphology after suturing. (G and H) Figures G and H illustrate the CSD. Figure H depicts the suture in place across the defect but not yet tightened.

Figure 2.

TVUS images before and after surgery. (A and B) Preoperative TVUS showing an anterior lower-segment CSD (red arrowheads) measuring 12×8 × 8mm and communicating with the endometrial cavity. (C) The RMT at the niche base is 1.4 mm. (D) TVUS at 1 month after laparoscopic folding suture repair: the niche has almost disappeared, RMT has increased to 7.0 mm, and the overlying myometrium is continuous.

Data Collection

Data were collected on the following:

1. Baseline characteristics: patient age, number of previous cesarean deliveries, duration of preoperative vaginal bleeding, and RMT at the defect site as measured by transvaginal ultrasound.

2. Perioperative details: intraoperative blood loss, complications, conversion to laparotomy, and uterine position.

3. Postoperative outcomes: menstrual duration at 3 months after surgery, time to first menses, RMT at 1-month follow-up, conception rates, time to conception, and the timing and mode of delivery.

RMT Measurements

Examinations were performed using a GE Voluson™ E10 system (5–9 MHz endocavity transducer) with patients in the lithotomy position and empty bladder. RMT was measured in the mid-sagittal plane as the shortest distance from the serosa to the defect apex. Two experienced sonographers, blinded to the study, performed all measurements. To ensure reliability, all ultrasound images were independently re-measured by two experienced sonographers who were blinded to the clinical data. The measurements showed high consistency with the original records, confirming the robustness of the RMT data.

Therapeutic efficacy was classified according to Wu et al¹¹ as follows:

1. Cure: Postoperative menstrual duration returned to the patient’s normal preoperative baseline (defined as ≤8 d).

2. Effective: Postoperative duration was shortened by ≥3 days compared to baseline but remained longer than the normal preoperative duration.

3. Ineffective: Menstrual duration was unchanged or shortened by <3 days.

The total effective rate was calculated as (cured + effective cases) / patients with follow-up data × 100%.

Statistical Analysis

All statistical analyses were performed using IBM SPSS Statistics (version 27.0). Normality was assessed using the Shapiro–Wilk test. Given the small sample size, continuous variables were uniformly reported as median with interquartile range (IQR) to ensure robustness, and non-parametric tests were applied accordingly. The Wilcoxon signed-rank test was used for pre- vs post-operative comparisons, and the Mann–Whitney U-test for between-group comparisons (pregnant vs non-pregnant). A two-tailed P < 0.05 was considered statistically significant.

Results

Perioperative Profile and Postoperative Improvements

This retrospective study had a follow-up period ranging from 3 months to 30 months, starting from the day of surgery. During the study period, 26 patients completed the study and were included in the final analysis. The baseline characteristics of the included patients are presented in Table 1.

Table 1.

Perioperative Profile and Postoperative Improvements (n = 26)

Variable	Median (IQR)
Age (years)	35.0 (32.8–36.2)
BMI (kg/m2)	23.0 (22.7–25.8)
Number of previous cesarean sections	1 (1–2)
Estimated blood loss (mL)	30 (20–50)
Intraoperative complications	0
Postoperative fever (>38°C)	0
Length of postoperative hospital stay (days)	4.0 (4.0–4.5)
Preoperative RMT (mm)	1.3 (1.0–1.7)
Postoperative RMT (mm)	6.5 (5.0–7.0)
Preoperative menstrual duration (days)	14.5 (10.0–15.0)
Postoperative menstrual duration (days)	7.0 (6.0–9.0)

Note: Continuous variables are presented as median with interquartile range (IQR).

Change in Menstrual Duration

Postoperative menstrual improvement was observed in 25 of 26 patients (96.2%). Twenty (76.9%) achieved menstrual durations ≤ 8 days, consistent with the normal range. Five (19.2%) continued to experience periods >8 days, but these were significantly shorter than preoperatively, with a median reduction of 5 days (range 4–10 days). Only one patient (3.8%) showed no appreciable change in menstrual length. Details are summarized in Table 2.

Table 2.

Changes in Menstrual Duration Before and After Surgery

Variable	Preoperative	Postoperative	Median Difference	P value
Menstrual duration (days)	14.5 (10.0–15.0)	7.0 (6.0–9.0)	5.0 (4.0–8.0)	< 0.001

Notes: Data are median (IQR). P values by Wilcoxon signed-rank test.

Postoperative Change in RMT

No patients experienced perioperative complications such as excessive bleeding, visceral injury, or conversion to open surgery. The RMT increased significantly from 1.3 mm (IQR 1.0–1.7) preoperatively to 6.5 mm (IQR 5.0–7.0) postoperatively (median increase 5.2 mm; Wilcoxon signed-rank test, P < 0.001; Figure 3). Notably, one patient, whose RMT increased from 0.4 mm preoperatively to 2.2 mm postoperatively, subsequently conceived via in-vitro fertilisation and embryo transfer (IVF-ET) and delivered a full-term infant without obstetric complications.

Figure 3.

Comparison of RMT before and after laparoscopic defect repair. In the pre-surgery group, the median RMT was 1.3 mm (IQR 1.0–1.7). In the post-surgery group, the median RMT was 6.5 mm (IQR 5.0–7.0). One outlier (3.0 mm) was identified in the pre-surgery group; no outliers were detected in the post-surgery group. A Wilcoxon signed-rank test showed a statistically significant difference between the pre- and post-surgery measurements (P < 0.001).

Postoperative Residual Defect

Postoperatively, a residual defect was still present in 5 patients. Despite this, all exhibited a marked increase in RMT and a reduction in menstrual duration compared to their preoperative assessments. Median postoperative RMT thickening was 2.5 mm (IQR 1.8–2.9) over baseline. Notably, three of these five patients achieved spontaneous pregnancy during follow-up. The incidence of residual defect decreased significantly from 50% (5/10) in the first 10 cases to 0% (0/16) in the subsequent 16 cases (P = 0.004, Fisher’s exact test). Detailed data are provided in Table 3.

Table 3.

Comparison of Residual Defect Rate Between the Initial 10 and Subsequent 16 Consecutive Cases

	n	CSD Present	No CSD
First 10 cases	10	5 (50%)	5 (50%)
Last 16 cases	16	0	16

Note: Data are presented as n (%).

Pregnancy Outcomes

Of the 16 patients who desired pregnancy and had at least 1 year of infertility, 12 (75%) achieved pregnancy during follow-up. Conception was spontaneous in 9 patients (56.3%); the remaining 3 pregnancies resulted from 6 IVF-ET cycles (3 successful). Regarding timing, 9 pregnancies occurred within the first year, one of which ended in early miscarriage (the patient subsequently conceived spontaneously 6 months later). Three further pregnancies occurred within 2.5 years, one of which was electively terminated. Cumulative pregnancy outcomes are presented in Figure 4; two participants remained pregnant at the time of analysis. All deliveries were accomplished by cesarean section. One neonate was delivered preterm at 34 0/7 weeks, one delivery was indicated by fetal tachycardia at 36 5/7 weeks, and one twin pregnancy was delivered at 36 0/7 weeks; all other infants were born at term. No serious obstetric complications, such as uterine rupture, occurred throughout pregnancy and at delivery. Two patients developed recurrent menstrual prolongation subsequent to cesarean delivery, and TVUS revealed a new CSD. Baseline characteristics were compared between pregnant and non-pregnant groups using the Mann–Whitney U-test. Only BMI differed significantly: median BMI was 22.9 kg/m² (IQR 21.2–23.9) in the pregnant group versus 26.2 kg/m² (IQR 23.4–28.6) in the non-pregnant group (P < 0.001). No statistically significant differences were observed between the two groups in age, number of previous cesarean sections, postoperative RMT, or increment in RMT.

Figure 4.

Cumulative incidence of pregnancy during 30 months of follow-up. Cumulative pregnancy rates were estimated using the Kaplan-Meier method. Of the 16 women attempting conception, 12 conceived during the follow-up period, and the remaining 4 were censored at the end of the study. Plus signs (+) indicate censored observations.

Discussion

The global rise in CS rates has been accompanied by an increasing incidence of CSD. CSD is associated with clinical issues such as AUB, chronic pelvic pain, and infertility, and its clinical significance is increasingly recognized. The incidence of infertility in patients with CSD is estimated to range from 4% to 19%.¹² With the implementation of China’s three-child policy, the issue of secondary infertility due to CSD has become increasingly pressing. In women with CSD whose RMT is < 3 mm, live-birth rates after IVF and intracytoplasmic sperm injection (ICSI) are significantly reduced.¹³ CSD may impair conception through the following pathways: (i) impaired sperm transport and motility, resulting from the accumulation of blood and inflammatory exudates within the defect, which creates a fluid reservoir that hampers sperm penetration and exhibits embryotoxicity;¹⁴ (ii) attenuated myometrial contractility around the defect, which may impair implantation or precipitate early pregnancy loss;¹⁴ (iii) alterations in the cervical microbiome, which can impair endometrial receptivity and result in secondary infertility. Recent data indicate that surgical repair of CSD induces a favorable shift in the vaginal microbial community, which may in turn promote conception;¹⁵ (iv) endometrial deficiency, ectopic endometrial tissue, and chronic inflammation within the CSD, which are associated with infertility.¹⁶ Therefore, during laparoscopic folding suture repair of a CSD, concomitant hysteroscopic resection of pathological tissue within the defect is recommended.

The mechanisms currently proposed for CSD-related prolonged menstrual duration include: (i) retention of menstrual blood within the defect, (ii) impaired drainage due to fibrotic tissue at the scar, and (iii) neovascularization that predisposes to focal bleeding within the defect.¹⁷ Laparoscopic folding suture repair of the CSD is performed under combined hysteroscopic and laparoscopic guidance. Hysteroscopy first delineates the exact boundaries of the defect; the laparoscopic approach then approximates and sutures the upper and lower margins of the scar, augmenting RMT without entering the uterine cavity. This reduces the risk of intrauterine infection, preserves uterine integrity, and is associated with minimal surgical trauma and a short required interval of contraception. Concurrently, hysteroscopy is used to resect fibrotic tissue at the inferior edge of the defect and to coagulate the intradefect endometrium, further enhancing overall surgical efficacy. While the Chinese Medical Association suggests that pregnancy may be considered as early as six months post-surgery,¹⁸ we observed two patients who conceived spontaneously two months postoperatively without contraception and subsequently achieved uncomplicated term deliveries. Therefore, this surgical approach can be offered to patients with an urgent fertility desire to alleviate the psychological burdens associated with delayed conception.

Conventional laparoscopic management of CSD typically involves excision of the thinned fibrotic defect and primary re-approximation of the adjacent healthy myometrium; however, de novo scar formation at the reconstructed site remains possible. A pooled analysis of three studies by Donnez¹⁹ reported CSD recurrence rates of 1.6%, 12%, and 33%, with the wide variation likely reflecting differences in sample size and surgeon expertise. Comparatively, the 49% incidence of residual defect reported by Abacjew-Chmylko et al²⁰ after excision and suture is notably higher than in the present study. Furthermore, the 27.3% persistence rate following laparoscopic folding suture repair observed by Peng et al²¹ also exceeds our findings.

Vikhareva et al²² stratified CSD size according to RMT: a large defect is defined as RMT ≤ 2.2 mm in women with one previous cesarean section and ≤ 1.9 mm in those with two or more prior sections, whereas RMT values above these thresholds are categorized as small defects. Based on the aforementioned classification, 88.5% (23/26) of patients in the present cohort had large defects. To date, studies evaluating the efficacy and pregnancy outcomes after CSD excision and repair have been limited by small sample sizes. Literature-documented pregnancy rates after laparoscopic CSD resection and repair are 62.1%²³ and 79.2%;²⁴ the rate observed in the present study falls between these two values. Zhang et al²⁵ reported that laparoscopic CSD excision and repair yielded amenorrhea improvement rates ranging from 82% to 100%. Although our pregnancy outcomes are encouraging, these results should be interpreted with caution due to the inherent selection bias and the absence of a comparative control arm in this study design. Nevertheless, when contextualized within the published literature, our findings fall at the upper limit of the reported range for similar procedures. This further substantiates the procedure’s safety and efficacy and supports the need for future controlled studies. Intraoperatively, we noted a significantly higher incidence of retroverted uteri compared to anteverted or mid-position uteri. This observation reinforces the association between uterine position and the presence of CSD, as previously documented.²⁶ In this study, BMI was significantly higher in the non-pregnant group than in the pregnant group (P < 0.001), consistent with existing literature reporting that a BMI ≥ 25 kg/m² is associated with reduced clinical pregnancy rate.²⁷

This study has several limitations. Its retrospective, single-center design, the relatively recent introduction of the surgical technique, and the loss of some patients to follow-up resulted in a limited sample size. Furthermore, RMT data were only obtained one month postoperatively, preventing analysis of long-term myometrial remodeling. In addition, due to the retrospective design, we were unable to assess AUB using validated tools such as PBAC or quality-of-life questionnaires; menstrual duration was used as a surrogate marker, which does not fully capture the complexity of AUB symptoms. While we have detailed intraoperative data on the eight patients who underwent round ligament shortening (successful conversion to anteverted position), the limited follow-up in this subgroup precluded a meaningful analysis of its long-term impact on CSD recurrence or fertility outcomes. Moreover, as a single-center retrospective study, our cohort may represent a selected population with a stronger desire for fertility. Unmeasured variables, such as male factor infertility and ovarian reserve, may have independently influenced pregnancy rates. Therefore, while the pregnancy outcomes are encouraging, they should be interpreted with caution, and causality cannot be inferred from this study design.

Despite these limitations, this series represents one of the highest follow-up rates reported to date for laparoscopic folding suture of CSD. Nevertheless, the long-term efficacy and RMT changes require further investigation. We plan to address these questions in a subsequent prospective cohort with follow-up at 1, 3, 6, and 12 months. Larger, multi-center, prospective studies are also warranted to validate the long-term outcomes and pregnancy success rates.

Conclusion

Laparoscopic folding suture repair of CSD appears to be a safe and feasible procedure that significantly shortens menstrual duration and improves reproductive outcomes in women with future fertility desires. However, due to the retrospective design, small sample size, and lack of a control group, these findings should be considered preliminary and require confirmation in large-scale, prospective controlled trials.

Disclosure

The authors declare no conflicts of interest in this work.