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

BACKGROUND: The rising rate of cesarean sections (CS) has led to an increased incidence of long long-term complications, including niche formation in the uterine scar. Niche development is associated with various gynecological 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 aim to evaluate the effect of single- versus double-layer closure of the uterine incision on live birth rate at a 3-year follow-up with secondary objectives focusing on gynecological, fertility and obstetric 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 undergoing a first CS 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 obstetric 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 830/1144 and 818/1148 responding to the 3-year questionnaire in the single-layer and double-layer closure. No differences were observed in live birth rates, also no differences in pregnancy rate, need for fertility treatments, mode of delivery or uterine ruptures in subsequent pregnancies. High rates of gynecological symptoms including spotting (30-32%), dysmenorrhea (47-49%) and sexual dysfunction (FSFI 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 CS. This challenges the current recommendation favoring double-layer closure, and we propose that surgeons can choose their preferred technique. Furthermore, the high risk of gynecological symptoms after a CS should be discussed with patients.