Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance

BACKGROUND: There is an ongoing controversy regarding the optimal uterine closure technique for preventing niche development. Single- and double-layer closures have been considered comparable in terms of niche incidence after primary cesarean delivery. However, rather than simply the presence of a n...

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Main Authors: Ha Thi Thu Nguyen, PhD, Giang Thi Tra Duong, MD, Dat Tuan Do, PhD, Thuong Thi Huyen Phan, PhD, Duc Anh Tran, MD, Toan Khac Nguyen, MD, Anh Duy Nguyen, PhD
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:AJOG Global Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666577825000681
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author Ha Thi Thu Nguyen, PhD
Giang Thi Tra Duong, MD
Dat Tuan Do, PhD
Thuong Thi Huyen Phan, PhD
Duc Anh Tran, MD
Toan Khac Nguyen, MD
Anh Duy Nguyen, PhD
author_facet Ha Thi Thu Nguyen, PhD
Giang Thi Tra Duong, MD
Dat Tuan Do, PhD
Thuong Thi Huyen Phan, PhD
Duc Anh Tran, MD
Toan Khac Nguyen, MD
Anh Duy Nguyen, PhD
author_sort Ha Thi Thu Nguyen, PhD
collection DOAJ
description BACKGROUND: There is an ongoing controversy regarding the optimal uterine closure technique for preventing niche development. Single- and double-layer closures have been considered comparable in terms of niche incidence after primary cesarean delivery. However, rather than simply the presence of a niche, its volume and residual myometrial thickness are the most potent factors in predicting gynecologic symptoms and subsequent pregnancy complications in women with cesarean scar defects. In addition, there is limited evidence on how uterine scars and niche sizes evolve over time. OBJECTIVE: This study aimed to compare the residual myometrial thickness and niche characteristics between the single-layer and double-layer uterine closure techniques and to evaluate the change in uterine scar characteristics from 6 to 12 months after cesarean delivery. STUDY DESIGN: This prospective randomized study was conducted from May 2022 to December 2024 at Hanoi Obstetrics and Gynecology Hospital. A total of 530 full-term pregnant women who underwent primary cesarean delivery were randomized into single- or double-layer, unlocked, continuous suture. The exclusion criteria included previous major uterine surgery and abnormal placenta (placenta previa or placenta accreta spectrum) in the current pregnancy. Women were invited for 2 consecutive follow-up visits within 10 days of menstruation at 6 months (n=429) and 12 months (n=381) after cesarean delivery. Transvaginal ultrasound was used to evaluate uterine ultrasound characteristics. If the niche was detected, 3-dimensional transvaginal ultrasound was applied to measure the niche volume via the Virtual Organ Computer-aided AnaLysis method. Complete-case analysis was performed to evaluate the change in uterine ultrasound characteristics between the 2 visits. RESULTS: Of 429 women who participated in the 6-month visit, 216 had single-layer closure, and 213 had double-layer closure. The niche incidence at the first assessment was similar for both uterine closure techniques, at 35.6% in the single-layer group and 31.9% in the double-layer group, respectively (P>.05). At 6 months after delivery, the double-layer technique resulted in greater residual myometrial thickness (4.3 vs 4.0 mm; P=.007), better healing ratio (69% vs 60%; P=.048), and a lower proportion of large niches with residual myometrial thickness of <3 mm (9.9% vs 19.4%; P=.033). The median niche volume in the single-layer group (62 mm3) at 6 months after delivery was significantly higher than that in the double-layer group (39 mm3) (P=.003). Of 381 women who completed both assessments, 194 had single-layer closure, and 187 had double-layer closure. The results between the single-layer and double-layer groups of the second visit at 12 months after delivery mirrored those at the first visit. In longitudinal follow-up evaluation, uterine scar characteristics were stable, and the overall proportion of niches remained consistent from 6 months to 12 months after delivery, at 34.4% and 36.0%, respectively (P>.05). There was an increase in niche length (5.0 vs 5.5 mm; P=.000) and niche volume (47 vs 55 mm3; P=.000) among the assessments. CONCLUSION: Although the niche incidence was similar between the 2 uterine closure techniques, the double-layer technique showed superior benefits, with greater residual myometrial thickness and healing ratio, lower large niche proportion, and smaller niche volume. The uterine scar characteristics were stable at 6 months after cesarean delivery, but the niche volume significantly increased over time. Future long-term follow-up research is needed to elucidate the relationship between niche size and clinical symptoms and to investigate the factors contributing to the temporal evolution of niche volume.
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spelling doaj-art-cc8222578f2b40f392abe061bb45dc7d2025-08-20T03:26:48ZengElsevierAJOG Global Reports2666-57782025-05-015210050710.1016/j.xagr.2025.100507Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a GlanceHa Thi Thu Nguyen, PhD0Giang Thi Tra Duong, MD1Dat Tuan Do, PhD2Thuong Thi Huyen Phan, PhD3Duc Anh Tran, MD4Toan Khac Nguyen, MD5Anh Duy Nguyen, PhD6National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)Corresponding author: Giang Thi Tra Duong, MD.; National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)National Center for Assisted Reproduction, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (H. Nguyen); Department of Obstetrics and Gynecology, Vietnam National University - University of Medicine and Pharmacy, Hanoi Vietnam (H. Nguyen); Department of High-Risk Pregnancy, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Duong and Do); Department of Obstetrics and Gynecology, Hanoi Medical University, Hanoi, Vietnam (Duong, Do, and A. Nyugen); Fetal Intervention Center, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Phan); Department of Delivery, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (Tran); Department of Gynecology, Hanoi Obstetrics and Gynecology Hospital, Hanoi, Vietnam (T. Nguyen); Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden (T. Nguyen); Department of High-Risk Pregnancy, National Hospital of Obstetrics and Gynecology, Hanoi, Vietnam (A. Nguyen)BACKGROUND: There is an ongoing controversy regarding the optimal uterine closure technique for preventing niche development. Single- and double-layer closures have been considered comparable in terms of niche incidence after primary cesarean delivery. However, rather than simply the presence of a niche, its volume and residual myometrial thickness are the most potent factors in predicting gynecologic symptoms and subsequent pregnancy complications in women with cesarean scar defects. In addition, there is limited evidence on how uterine scars and niche sizes evolve over time. OBJECTIVE: This study aimed to compare the residual myometrial thickness and niche characteristics between the single-layer and double-layer uterine closure techniques and to evaluate the change in uterine scar characteristics from 6 to 12 months after cesarean delivery. STUDY DESIGN: This prospective randomized study was conducted from May 2022 to December 2024 at Hanoi Obstetrics and Gynecology Hospital. A total of 530 full-term pregnant women who underwent primary cesarean delivery were randomized into single- or double-layer, unlocked, continuous suture. The exclusion criteria included previous major uterine surgery and abnormal placenta (placenta previa or placenta accreta spectrum) in the current pregnancy. Women were invited for 2 consecutive follow-up visits within 10 days of menstruation at 6 months (n=429) and 12 months (n=381) after cesarean delivery. Transvaginal ultrasound was used to evaluate uterine ultrasound characteristics. If the niche was detected, 3-dimensional transvaginal ultrasound was applied to measure the niche volume via the Virtual Organ Computer-aided AnaLysis method. Complete-case analysis was performed to evaluate the change in uterine ultrasound characteristics between the 2 visits. RESULTS: Of 429 women who participated in the 6-month visit, 216 had single-layer closure, and 213 had double-layer closure. The niche incidence at the first assessment was similar for both uterine closure techniques, at 35.6% in the single-layer group and 31.9% in the double-layer group, respectively (P>.05). At 6 months after delivery, the double-layer technique resulted in greater residual myometrial thickness (4.3 vs 4.0 mm; P=.007), better healing ratio (69% vs 60%; P=.048), and a lower proportion of large niches with residual myometrial thickness of <3 mm (9.9% vs 19.4%; P=.033). The median niche volume in the single-layer group (62 mm3) at 6 months after delivery was significantly higher than that in the double-layer group (39 mm3) (P=.003). Of 381 women who completed both assessments, 194 had single-layer closure, and 187 had double-layer closure. The results between the single-layer and double-layer groups of the second visit at 12 months after delivery mirrored those at the first visit. In longitudinal follow-up evaluation, uterine scar characteristics were stable, and the overall proportion of niches remained consistent from 6 months to 12 months after delivery, at 34.4% and 36.0%, respectively (P>.05). There was an increase in niche length (5.0 vs 5.5 mm; P=.000) and niche volume (47 vs 55 mm3; P=.000) among the assessments. CONCLUSION: Although the niche incidence was similar between the 2 uterine closure techniques, the double-layer technique showed superior benefits, with greater residual myometrial thickness and healing ratio, lower large niche proportion, and smaller niche volume. The uterine scar characteristics were stable at 6 months after cesarean delivery, but the niche volume significantly increased over time. Future long-term follow-up research is needed to elucidate the relationship between niche size and clinical symptoms and to investigate the factors contributing to the temporal evolution of niche volume.http://www.sciencedirect.com/science/article/pii/S2666577825000681double-layer uterine closurelarge nicheniche volumeresidual myometrial thicknesssingle-layer uterine closure
spellingShingle Ha Thi Thu Nguyen, PhD
Giang Thi Tra Duong, MD
Dat Tuan Do, PhD
Thuong Thi Huyen Phan, PhD
Duc Anh Tran, MD
Toan Khac Nguyen, MD
Anh Duy Nguyen, PhD
Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
AJOG Global Reports
double-layer uterine closure
large niche
niche volume
residual myometrial thickness
single-layer uterine closure
title Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
title_full Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
title_fullStr Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
title_full_unstemmed Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
title_short Single- vs double-layer uterine closure of the cesarean scar in niche development: the Nicest StudyAJOG Global Reports at a Glance
title_sort single vs double layer uterine closure of the cesarean scar in niche development the nicest studyajog global reports at a glance
topic double-layer uterine closure
large niche
niche volume
residual myometrial thickness
single-layer uterine closure
url http://www.sciencedirect.com/science/article/pii/S2666577825000681
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