Evaluation of Shear Wave Elastography as a Predictor for the Outcome of Induction of Labor in Nulliparous Women

Objective】Objective To explore the feasibility and application value of cervical elastography (SWE) in predicting the delivery outcomes of labor induction (IOL) in nulliparous women.Methods From January 2024 to August 2025 in Lingnan Hospital, the Third Affiliated Hospital of Sun Yat-sen University, 91 nulliparous women who used cervical dilation balloons to induce labor were selected for a prospective study, with 62 final vaginal deliveries (VD group) and 29 cesarean deliveries (CS group). SWE was used to evaluate the hardness of different parts of the cervix before IOL. The differences in prenatal cervical SWE and Bishop scores (BS) between the two groups were compared and their predictive value for IOL outcomes was analyzed.Results There were significant differences in the SWEs of the cervical canal (M3 near the inner mouth of the cervical canal and M4 near the outer mouth of the cervical canal) between the two groups, and the SWE values in the VD group were lower than those in the CS group (M3: 4.33 ± 1.40 vs. 6.71 ± 3.16, P < 0.001; M4: 4.79 ± 2.00 vs. 6.23 ± 2.42, P = 0.004). There was no significant difference between the two groups in the remaining SWE values. Moreover, there was no significant difference between the two groups in BS and its individual indicators. After univariate and multivariate analysis, excluding factors such as age, gestational age, height BMI, and the cause of IOL, only the internal cervical canal SWE (M3) [P = 0.028, OR: 0.63 (95% CI: 0.41~ 0.95) ] was the influencing factor to determine the success rate of labor induction in primitive women. The ROC curve was used to evaluate the predictive value of each ultrasound index and BS on the outcome of induction of labor in primitives. The results showed that SWE (M3) had the highest predictive value for the success of induction of labor in primitives, with an AUC of 0.77, a sensitivity of 80.6%, and a specificity of 64.3%, which was significantly higher than that of traditional BS (AUC = 0.54, a sensitivity of 85.5%, and a specificity of 21.4%). The difference was statistically significant by Delong test (Z = 2.92, P = 0.004).Conclusions As an evaluation method for cervical stiffness, SWE at the internal cervical canal os can be used to predict the IOL outcome in nulliparous women. It has obvious advantages over traditional BS in prediction accuracy and can serve as an important auxiliary means for the clinical evaluation of IOL outcomes.