Transvaginal ultrasound evaluation of uterine scar in pregnant women with a previous cesarean section

Background Many studies have shown that the thickness of the lower uterine segment (LUS) is correlated to the risk of uterine scar dehiscence. Transvaginal sonography (TV US) has been used to predict uterine dehiscence by measuring the LUS thickness near term. Aims In this study, the main aim was to assess the thickness of the LUS and determine its integrity in pregnant women at term with previous cesarean section (CS) through TV US. Patients and methods The study involved 200 pregnant females at term (gestational age between 36 and 38 weeks) with a history of one previous CS, who were attending the Gynecology and Obstetrics Department at Tanta University Hospital. The study started from January 2019 till September 2020. Results There was highly significant correlation between LUS thickness measured by TV US, scar shape, and continuity with intraoperative findings as categorized into four grades (r=−0.783 and P=0.000). The cutoff value was 2.3 mm; at this thickness the risk of dehiscence increased, with a sensitivity of 94.1%, specificity of 96.4%, and an accuracy of 95% (area under the curve=0.935). Conclusion TV US is a reliable method for the assessment of the risk of uterine rupture by measuring the LUS thickness in women with previous CS. The cutoff value is 2.3 mm with a sensitivity of 94.1% and specificity of 96.4%. Accuracy was 95%.