Single-layer versus double-layer uterine closure technique in niche development among women with full-term primary C-sections: A randomized clinical trial

This study aims to compare niche incidence between single- and double-layer uterine closure techniques and describe related factors among women with full-term primary C-section. From May 2022 to March 2023 at Hanoi Obstetrics and Gynecology Hospital, a double-blind, randomized controlled trial was performed on 116 participants (64 in single- and 52 women in double-layer group). The uterine scar was evaluated by transvaginal ultrasound at 12 months postoperatively. The overall niche was 43.1%. There was no difference in niche incidence and residual myometrial thickness between single - and double group (48.4% versus 36.5%; 4.4mm versus 4.6mm, respectively). The healing ratio was better in the latter group (0.60 vs. 0.66, p<0.05). The mean volume of niche was 64mm3. All women were in the mild niche, with a VTS score ≤ 2. The retroverted uterus among women with niche was 56%, higher significantly than women without niche (34.8%). In conclusion, on the hand of well-trained surgeons, there were no difference in niche incidence and RMT between single- and double-layer uterine closure techniques. Retroverted uterus was the main factor contributed to development of niche. Further studies are needed to evaluate the progress of the niche in a longer span and to prevent retroverted uterus.