Factors Associated to the Presence of Isthmocele Diagnosed by Pelvic Ultrasound, Magnetic Resonance Imaging or Diagnostic Hysteroscopy: A Cross-Sectional Study

We aimed to analyze the prevalence of isthmocele and factors associated with its onset within a cohort of women with previous history of cesarean section. A cross-sectional study with 90 women assessed from 2020 to 2022. Isthmocele was a composite variable diagnosed by transvaginal ultrasound (TVUS), magnetic resonance imaging (MRI) and/or diagnostic hysteroscopy (DxHys) and were asked about clinical symptoms, sociodemographic and obstetrical history and quality of life by the WHO-QOL questionnaire. Univariate and multivariate analysis (odds ratio (OR) plus 95% confidence intervals—CI) were performed to seek factors associated with the presence of isthmocele (5% significance level).The prevalence of isthmocele after combining MRI, TVUS and DxHys was 63.3% (n = 57). Women with isthmocele presented a higher body mass index (BMI) measured during delivery (32.70 ± 6.07 vs. 28.28 ± 9.86 kg/m²;p < 0.05) than women without isthmocele. Other sociodemographic variables, obstetrical history and WHO-QOL subdomains did not differ between groups. Within women with isthmocele, the residual myometrial mantle had an average of 4.97 ± 1.57 cm. Uterine volume was higher in the isthmocele group (103.95 vs. 81.34 cm³; p = 0.08), but with no statistical difference. Multivariate analysis (logistic regression) has reported that the factors associated with isthmocele were: higher BMI during delivery (aOR = 1.26[1.07–1.49];p < 0.05); longer interpartum interval (aOR = 1.22[1.03–1.46];p = 0.02) and presence of more than two cesarean sections (aOR = 2.16[1.16–4.01];p = 0.02). We concluded that a high prevalence of isthmocele was found. Women with previous cesarean section, with higher BMI during delivery and longer interdelivery interval were risk factors for the presence of isthmocele.