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Double or Single Layer Closure for Best Cesarean-Section Outcomes?


  • Niche on ultrasound describes a triangular anechoic area at the site of a previous cesarean section
    • Seen with saline or gel contrast hysterosonography
    • Residual myometrium thickness (RMT) at apex of niche is thin
  • Possible that RMT thickness related to closure technique
  • Stegwee et al. (BJOG, 2017) examined whether uterine closure technique after cesarean section has an impact on maternal and ultrasound outcomes


  • Systematic review and meta-analysis
  • Literature search of randomized controlled trials (RCTs) or prospective cohort studies that evaluated uterine closure techniques and reported on ultrasound findings, perioperative or long-term outcomes
  • The following techniques were included in the analyses
    • Single- versus double-layer closure
    • Locked versus unlocked suturing
    • Inclusion versus exclusion of the decidua
  • Outcomes
    • Ultrasound findings post cesarean section
    • Intra-operative and short-term post-operative findings
    • Gynecologic symptoms
    • Reproductive outcomes


  • Meta analyses performed using twenty studies
  • Data was analyzed from 15,053 women
  • RMT decreased by 1.26 mm after single- vs double-layer closure (95% CI -1.93 to -0.58; P=0.0003)
    • More pronounced with locked sutures
  • Healing ratio (RMT/adjacent myometrium thickness) was decreased with single-layer closure (Weighted mean difference -7.74%, 95% CI -13.31 to -2.17)
    • More pronounced with locked sutures
  • Niche more common when the decidua was excluded (RR 1.71, 95% CI 1.11-2.62)
  • Dysmenorrhea occurred more often in the single-layer group (RR 1.23, 95% CI 1.01-1.48)
  • Incidence of uterine rupture was similar (RR 1.91, 95% CI 0.63-5.74) between groups


  • Double-layer unlocked sutures were preferable to single-layer locked sutures regarding RMT, healing ratio and dysmenorrhea
  • Niche prevalence increased with excluded decidua

Learn More – Primary Sources:

Uterine caesarean closure techniques affect ultrasound findings and maternal outcomes: a systematic review and meta-analysis.

Does Adding a 2nd Layer to Uterine Closure of a Cesarean Section Alter Outcomes?


  • There are randomized studies evaluating the addition of the second layer, but generally following locked suture technique  
  • Bennich et al. (Ultrasound Obstet Gynecol, 2016) investigated the impact of adding a second layer to a single unlocked closure of a cesarean uterine incision on residual myometrial thickness (RMT) as a proxy for uterine rupture risk 


  • Randomized double-blind controlled trial (2008-2013) 
  • Nulliparous women > 37 weeks scheduled for cesarean section  
  • Women randomized to 
    •  Single-layer technique (continuous) 
    •  Double-layer technique 2nd layer (continuous – up to 3 separate sutures for hemostasis if needed)  
  • At discharge 
    • Transabdominal ultrasound  
  • At 5 months  
    • Saline contrast sonohysterography at a minimum of 5 months postpartum 
  • Ultrasound examiners were blinded to closure technique 


  • Single layer n= 35; double-layer n= 38 
  • No difference in age, BMI or perioperative characteristics (e.g., duration of surgery) between groups  
  • When comparing groups, there were no difference in the RMT whether at discharge (mean ± SD, 20.2 ± 8.0 mm vs 21.0 ± 9.7 mm) or after 5 months postpartum (5.7 ± 2.9 mm vs 5.7 ± 2.2 mm) 
    • RMT was approximately half that of the normal myometrium at both examinations 
  • There were also no differences in gestational age at delivery, duration of surgery and perioperative blood loss 


  • Double-layer closure of C-section incision does not increase RMT compared with single-layer closure when an unlocked technique is used 
  • Some previous studies demonstrated a larger RMT with double-layer used locked first-layer 
  • Authors suggest that unlocked technique for the first-layer is at least as good as double layer, and a first-layer locking technique may result in reduced RMT and possible increase risk for rupture 

Learn More – Primary Sources

Impact of adding a second layer to a single unlocked closure of a Cesarean uterine incision: randomized controlled trial 

Do Different Surgical C-Section Techniques Affect Outcomes?


This study by the Coronis Collaborative Group (Lancet, 2016) aimed to determine if there were differences in maternal morbidity depending on which of five surgical techniques for caesarean section a woman received.


Randomized Control Trial


13,153 women were followed up with for a mean duration of 3.8 years after receiving a C-section through one of five surgical techniques. The five pairs of alternative surgical techniques surveyed were blunt vs. sharp abdominal entry; exteriorization of the uterus vs. intra-abdominal repair; single vs. double layer closure of the uterus; closure vs. non-closure of the peritoneum; and chromic catgut vs. polyglactin-910 sutures.

The study found no evidence to prefer one surgical technique over another based on the following outcomes

  • Blunt vs sharp abdominal entry
    • Abdominal hernias: no difference (adjusted relative risk 0·66; 95% CI 0·39–1·11)
  • Exteriorization vs abdominal repair
    • Infertility: no difference (adjusted relative risk 0·91, 0·71–1·18)
    • Ectopic pregnancy: no difference (adjusted relative risk 0·50, 0·15–1·66)
  • Single vs double uterine closure
    • Maternal death: no difference (adjusted relative risk 0·78, 0·46–1·32)
    • Composite of pregnancy complications (adjusted relative risk 1·20, 0·75–1·90)
  • Peritoneal closure vs non-closure
    • Pelvic adhesions (related complications such as infertility): no difference (adjusted relative risk 0·80, 0·61–1·06)
  • Chromic catgut vs polyglactin-910 sutures
    • Adverse pregnancy outcomes in a subsequent pregnancy, such as uterine rupture: no difference (adjusted relative risk 3·05, 0·32–29·29).


  • Overall, severe adverse outcomes were uncommon in these settings
  • Determination of technique will take in to account other factors including time and cost

Learn More – Primary Sources:

Caesarean section surgical techniques: 3 year follow-up of the CORONIS fractional, factorial, unmasked, randomised controlled trial

Impact of single- vs double-layer closure on adverse outcomes and uterine scar defect: a systematic review and meta-analysis