Prospective Evaluation of the Ultrasound Signs Proposed for the Description of Uterine Niche in Nonpregnant Women

Noa Feldman, Ron Maymon, Eric Jauniaux, Danielle Manoach, Matan Mor, Ewa Marczak, Yaakov Melcer

Research output: Contribution to journalArticlepeer-review


As cesarean delivery (CD) rates have exponentially increased worldwide during the last 2 decades, the development of a "gniche,"or a CD scar defect (also called isthmocele), has arisen as a key factor associated with secondary gynecological and obstetrical complications. In terms of subsequent pregnancies, these defects have been indirectly associated with increased rates of placenta accreta, iatrogenic obstetric complications, and preterm birth. Endometrium tethering in a niche can serve as an intermenstrual blood or fluid reservoir. Experts of the European Niche Taskforce participated in a standardization of uterine niche evaluation via a Delphi procedure in 2019, in consideration of nonpregnant women. This evaluation also included a consensus-formed description of ultrasound signs of a uterine niche. This study aimed for a prospective evaluation of ultrasound signs in terms of their relationship with clinical factors for women who had undergone one prior CD. Between December 2019 and December 2020, this prospective cohort study was conducted at the Department of Obstetrics and Gynecology, Shamir Medical Centre, Israel. All participants granted written informed consent for enrollment. Women with one previous term(≥37 weeks) CD were offered participation in the study; all CDs performed used a low transverse uterine incision and closed the uterus in 2 unlocked layers. Multiple gestations, more than one prior CD, and previous incisions other than low transverse were excluded. Patients were divided into 2 subgroups based on labor stage at the time of their CD. Women undergoing elective CD or emergent CD at a cervical dilatation ≤4 cm (latent phase) were put into subgroup A, whereas women who had their CD at any stage >4 cm (active phase) were included in subgroup B. Of a total 160 women recruited (45 elective CD, 115 emergent CD), 41 women (25.6%) were diagnosed with a uterine niche. Subgroup A had 109 (68.1%) women, whereas subgroup B had 51 (31.9%). Subgroup A also demonstrated a significantly higher incidence of a niche positioned above the vesicovaginal fold in the uterus when compared with subgroup B. (P = 0.0002). Standardized criteria provided by the European Niche Taskforce were used, and the authors found that women with elective CDs were more likely to present with a uterine niche within 4 to 12 months after delivery when compared with those with emergency CD in active labor. In addition, when hysterotomies are performed cervical dilations of .4, niches and simple scars are more often located above the vesicovaginal fold. Study strengths include its prospective design, which allowed standardized transvaginal ultrasound examination for all study participants, who, during the study period, were found to be in the category of having had one previous CD at term. In addition, measurements for the study were made via consensus criteria of the European Niche Taskforce. Limitations included the single-institution design of the study (thereby limiting the generalizability of the results), variable time intervals between delivery and follow-up scan (during the COVID-19 pandemic), a lack of longitudinal data on uterine niche development, and possible changes of the CD scar remodeling with progressing time after hysterotomy. Ultimately, increasing incidence of CD has raised the question as to the value of ultrasound evaluation of the uterine scarification process. This study adds to our understanding of the impact of various CD types and various uterine closure techniques on risks of long-term gynecological and obstetric complications.

Original languageEnglish
Pages (from-to)572-574
Number of pages3
JournalObstetrical and Gynecological Survey
Issue number10
StatePublished - 1 Oct 2022


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