Single-Layer Versus Double-Layer Uterine Closure After Primary Cesarean Section

NCT07611331 | Completed DMC

• 1 other identifier: 31/26
• Study Type: interventional
• Target: 384
• Locations: 1 country
• Sites: 1

Brief Summary

This study compares two surgical techniques for closing the uterus after cesarean section: single-layer versus double-layer closure. The primary objective is to determine which technique results in better uterine scar healing, measured by residual myometrial thickness (RMT) and cesarean scar defect (niche) prevalence at 6 weeks and 6 months postoperatively. BACKGROUND: Cesarean section is one of the most common surgeries worldwide. After fetal delivery, the uterine incision must be closed by suture. Poor scar healing can lead to niche formation, abnormal bleeding, pelvic pain, dyspareunia, and complications in future pregnancies including uterine rupture and placenta accreta. INTERVENTION: Participants are randomized 1:1 to receive either:

• Single-layer closure: one continuous non-locking suture through full myometrial thickness
• Double-layer closure: two successive extra-mucosal non-locking sutures excluding the decidua ASSESSMENTS: Transvaginal ultrasound at 6 weeks and 6 months measures RMT and niche presence. Standardized symptom questionnaires assess pelvic pain, spotting, dysmenorrhea, and dyspareunia. ELIGIBILITY: Women aged 18-45 years undergoing primary cesarean section with singleton pregnancy at term (gestational age ≥ 37 weeks). ENROLLMENT: 384 participants (192 per group) SETTING: Department of Obstetrics and Gynecology, Hedi Chaker University Hospital, Sfax, Tunisia FOLLOW-UP: 6 months per participant in which the patients attend 2 follow-up visits: First visit 6 weeks after surgery. Second visit at 6 months after surgery .And have a pelvic ultrasound at each visit

Conditions

Cesarean Scar Defect (Isthmococele); Pelvic Pain; Spotting; Amenorrhea Secondary; Metrorrhagia

Keywords

single layer; double layer; Residual Myometrial Thickness (RMT); Ultrasound; Isthmocele-niche; Cesarean; Scar healing

Outcome Measures

Primary Outcomes (2)

• Residual Myometrial Thickness (RMT) at the Cesarean Scar at 6 Weeks and 6 Months

  Residual myometrial thickness (RMT) measured in millimeters at the thinnest point of the uterine scar using standardized transvaginal two-dimensional ultrasound, performed by blinded sonographers according to the protocol of Naji et al. (2012). RMT compared between single-layer (HPU) and double-layer (HDP) closure groups at 6 weeks and 6 months postoperatively.

  6 weeks and 6 months after cesarean section

• Prevalence of Cesarean Scar Defect (Niche) at 6 Weeks and 6 Months Postoperatively

  Cesarean scar defect (niche) defined as a hypoechoic triangular indentation at the site of the uterine incision with depth ≥ 2mm or residual myometrial thickness (RMT)/adjacent myometrial thickness (AMT) ratio \< 50%, detected by standardized transvaginal two-dimensional ultrasound. Prevalence compared between single-layer (HPU) and double-layer (HDP) closure groups at 6 weeks and 6 months postoperatively.

  6 weeks and 6 months after cesarean section

Secondary Outcomes (9)

• Prevalence of Gynecological Symptoms Related to Cesarean Scar Defect

  Day 10, 6 weeks, and 6 months after cesarean section

• Identification of Independent Risk Factors for Cesarean Scar Defect Formation

  6 weeks and 6 months after cesarean section

• Cesarean Scar Defect Linear Dimensions

  6 weeks and 6 months after cesarean section

• Cesarean Scar Defect Volume

  6 weeks and 6 months post-cesarean

• Operative Duration of Hysterorrhaphy and Total Cesarean Section

  preoperative (during cesarean section procedure)

Other Outcomes (3)

• Mediation Analysis: Role of Early Scar Defect in Late Outcome

  6 weeks and 6 months after cesarean section

• Development of a Clinical Symptom-Based Predictive Score for Cesarean Scar Defect

  6 months after cesarean section

• Identification of a Functional RMT Threshold Associated with Symptomatic Risk

  6 weeks and 6 months after cesarean section

Study Arms (2)

Single-layer Uterine Closure (HPU)

ACTIVE COMPARATOR

Participants allocated to this arm undergo primary cesarean section with single-layer uterine closure (hysterorrhaphy). After fetal and placental extraction, the uterine incision is closed in one single layer using a continuous absorbable suture (polyglactin 910 or equivalent), which approximates the myometrium in a running unlocked pattern. No second imbricating layer is performed. Additional interrupted sutures (reinforcement stitches) may be placed if necessary for bleeding control. All participants are followed postoperatively with standardized transvaginal ultrasound assessments at 6 weeks and 6 months to evaluate residual myometrial thickness (RMT) and cesarean scar defect (niche) development, as well as clinical symptom monitoring.

Procedure: Single-layer hysterorrhaphy at primary cesarean section

Double-layer Uterine Closure (HDP)

EXPERIMENTAL

articipants allocated to this arm undergo primary cesarean section with double-layer uterine closure (hysterorrhaphy). After fetal and placental extraction, the uterine incision is closed in two distinct layers using a continuous absorbable suture (polyglactin 910 or equivalent). The first layer approximates the myometrium with a running unlocked suture. The second layer invaginates the first using a continuous suture to reinforce the closure and improve hemostasis. Additional interrupted sutures (reinforcement stitches) may be placed if necessary for bleeding control. All participants are followed postoperatively with standardized transvaginal ultrasound assessments at 6 weeks and 6 months to evaluate residual myometrial thickness (RMT) and cesarean scar defect (niche) development, as well as clinical symptom monitoring.

Procedure: Double-layer hysterorrhaphy at primary cesarean section

Interventions

Double-layer hysterorrhaphy at primary cesarean section PROCEDURE

After fetal and placental delivery, the uterine incision is closed in two layers using continuous absorbable suture (polyglactin 910). Layer 1: running suture approximating the full myometrial thickness. Layer 2: continuous imbricating suture reinforcing the first layer and improving hemostasis. Additional reinforcement sutures placed if needed. Aims to optimize uterine scar healing and reduce cesarean scar defect (niche) formation.

Also known as: Two-layer uterine closure, Double-layer uterine closure, HDP technique

Double-layer Uterine Closure (HDP)

Single-layer hysterorrhaphy at primary cesarean section PROCEDURE

After fetal and placental delivery, the uterine incision is closed in one single layer using a continuous absorbable suture (polyglactin 910) approximating the full myometrial thickness in a running pattern. No second reinforcement layer is performed. Additional reinforcement sutures are placed if needed. This represents the conventional standard technique for uterine closure at cesarean section.

Also known as: One-layer uterine closure, Single-layer uterine closure, HPU technique

Single-layer Uterine Closure (HPU)

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Women aged 18 years or older
• Singleton pregnancy
• Gestational age ≥ 37 weeks (term pregnancy)
• Scheduled or emergency primary cesarean section (first cesarean delivery, no previous uterine scar)
• Low transverse uterine incision (Pfannenstiel or Joel-Cohen approach)
• Ability to provide written informed consent
• Willingness to attend follow-up visits at 6 weeks and 6 months postoperatively
• Patient affiliated to a social security system or equivalent healthcare coverage

You may not qualify if:

• Previous uterine surgery (prior cesarean section, myomectomy, uterine perforation, or any procedure leaving a uterine scar)
• Multiple pregnancy (twins or higher-order multiples)
• Preterm delivery (gestational age \< 37 weeks)
• Classical (vertical) or inverted T uterine incision
• Placenta previa or placenta accreta spectrum disorder
• Active uterine infection or chorioamnionitis at time of surgery
• Coagulation disorders or anticoagulant therapy
• Immunosuppressive therapy or conditions affecting wound healing (systemic corticosteroids, immunosuppressants)
• Severe maternal comorbidities (uncontrolled diabetes, connective tissue disorders, chronic renal failure)
• Participation in another interventional clinical trial
• Patient unable to attend scheduled follow-up visits
• Patient unable to understand or sign informed consent
• Fetal demise or major fetal malformation

Sponsors & Collaborators

• Hédi Chaker Hospital: lead

Study Sites (1)

Hedi Chaker university hospital

Sfax, Sfax Governorate, 3000, Tunisia

Location

Related Publications (5)

• Bij de Vaate AJ, van der Voet LF, Naji O, Witmer M, Veersema S, Brolmann HA, Bourne T, Huirne JA. Prevalence, potential risk factors for development and symptoms related to the presence of uterine niches following Cesarean section: systematic review. Ultrasound Obstet Gynecol. 2014 Apr;43(4):372-82. doi: 10.1002/uog.13199.

  PMID: 23996650 BACKGROUND

• Di Spiezio Sardo A, Saccone G, McCurdy R, Bujold E, Bifulco G, Berghella V. Risk of Cesarean scar defect following single- vs double-layer uterine closure: systematic review and meta-analysis of randomized controlled trials. Ultrasound Obstet Gynecol. 2017 Nov;50(5):578-583. doi: 10.1002/uog.17401. Epub 2017 Oct 9.

  PMID: 28070914 BACKGROUND

• Roberge S, Demers S, Berghella V, Chaillet N, Moore L, Bujold E. Impact of single- vs double-layer closure on adverse outcomes and uterine scar defect: a systematic review and metaanalysis. Am J Obstet Gynecol. 2014 Nov;211(5):453-60. doi: 10.1016/j.ajog.2014.06.014. Epub 2014 Jun 6.

  PMID: 24912096 BACKGROUND

• Stegwee SI, Ben AJ, El Alili M, van der Voet LF, de Groot CJM, Bosmans JE, Huirne JAF; 2Close study group. Cost-effectiveness of single-layer versus double-layer uterine closure during caesarean section on postmenstrual spotting: economic evaluation alongside a randomised controlled trial. BMJ Open. 2021 Jul 2;11(7):e044340. doi: 10.1136/bmjopen-2020-044340.

  PMID: 34215598 BACKGROUND

• Jordans IPM, de Leeuw RA, Stegwee SI, Amso NN, Barri-Soldevila PN, van den Bosch T, Bourne T, Brolmann HAM, Donnez O, Dueholm M, Hehenkamp WJK, Jastrow N, Jurkovic D, Mashiach R, Naji O, Streuli I, Timmerman D, van der Voet LF, Huirne JAF. Sonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure. Ultrasound Obstet Gynecol. 2019 Jan;53(1):107-115. doi: 10.1002/uog.19049.

  PMID: 29536581 BACKGROUND

Related Links

• Jordan et al. 2019 - European Niche Task Force consensus on sonographic examination of uterine : nicheSonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure

MeSH Terms

Conditions

Pelvic Pain; Metrorrhagia

Condition Hierarchy (Ancestors)

Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Uterine Hemorrhage; Uterine Diseases; Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Diseases; Hemorrhage; Pathologic Processes

Study Officials

• Derbel Mohamed, Professor

  Department of obstetric and gynaecology of Hedi Chaker sfax

  PRINCIPAL INVESTIGATOR

• Khanfir Fatma, Professor

  Department of obstetric and gynaecology of Hedi Chaker sfax

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: Participants were not informed of the uterine closure technique used. Surgeons were not blinded due to the nature of the intervention. Ultrasound outcome assessors were blinded to group allocation.
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Medical resident

Model Details: A prospective, randomized, parallel-group trial comparing two uterine closure techniques during primary cesarean section. Participants were randomized in a 1:1 ratio to receive either single-layer hysterorrhaphy (HPU) or double-layer hysterorrhaphy (HDP). Blinding was maintained for the ultrasound evaluators. Uterine scar quality (RMT and niche prevalence) and clinical symptoms are assessed at 6 weeks and 6 months post-surgery.

Study Record Dates

• First Submitted: May 9, 2026
• First Posted: May 28, 2026
• Study Start: January 1, 2025
• Primary Completion: January 1, 2026
• Study Completion: April 30, 2026
• Last Updated: May 28, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)