Objective: Previous cesarean delivery is a major indication for repeat cesarean section. However, a substantial proportion of women enter spontaneous labor before the planned date, increasing maternal and neonatal risks. This study aimed to assess whether selected transvaginal ultrasonographic markers can predict early labor in women scheduled for elective cesarean delivery. Material and Methods: In this prospective cohort study, 102 women with prior cesarean delivery were scheduled for elective cesarean at 38-39 weeks. Cervical length, anterior uterocervical angle (UCA), and lower uterine segment thickness (LUT) were measured by transvaginal ultrasonography after 34-35 weeks. Women who entered spontaneous labor and required urgent cesarean delivery before the scheduled date were compared with those who delivered as planned. Results: Twenty -six women (25.5%) required urgent cesarean delivery. The urgent delivery group had significantly thinner LUT (4.7±1.4 mm vs. 8.6±2.4 mm, p<0.01) and wider UCA (105° vs. 95°, p<0.01). Cervical length did not significantly differ between the groups. Logistic regression identified LUT as the strongest independent predictor of early labor (odds ratio 0.392, 95% confidence interval 0.256-0.604, p<0.01). Receiver operating characteristic analysis showed that a LUT cut-off value of <6.5 mm predicted early labor with 88.5% sensitivity and 76.7% specificity (area under the curve 0.908). Conclusion: About one-fourth of women scheduled for elective cesarean delivery may enter labor before the planned date. Thinner LUT and wider UCA provide meaningful predictive information for identifying women at risk of early labor. Incorporating these sonographic markers into preoperative assessment may support individualized cesarean timing and help reduce unplanned procedures.
Sönmez et al. (2026) studied this question.