The Predictive Role of Cervical Volume, Cervical Length, and Uterocervical Angle for Preterm Birth

Predictive tests for preterm birth are considered extremely important considering the associated morbidities. Here, we aimed to assess the predictive role of cervical volume for preterm birth and compare this role with uterocervical angle and cervical length. Additionally, we aimed to evaluate the success of combinations of cervical volume, uterocervical angle, and cervical length in predicting preterm birth.

A total of 485 pregnant women between 16 and 24th gestational weeks of gestation were included in this prospective observational study. Then, the patients were grouped as preterm and term births. The clinical characteristics, obstetric outcomes, and sonographic findings including uterocervical angle, cervical length, and cervical volume were compared between groups. The predictive roles of sonographic findings for preterm birth were analyzed by receiver operating characteristic curve and regression analysis.

Cervical length ≤ 35.7 mm predicted preterm birth with 81.16% sensitivity and 79.81% specificity (p < 0.001, AUC = 0.843) while uterocervical angle > 94.9° predicted it with 98.55% sensitivity and 54.57% specificity (p < 0.001, AUC = 0.751). Cervical volume ≤ 30.4 mm³ predicted preterm birth with 86.96% sensitivity and 77.4% specificity (p < 0.001, AUC = 0.886). No significant difference was found between cervical length and cervical volume, both of which are superior to uterocervical angle in predicting preterm birth. The combination of cervical length, uterocervical angle, and cervical volume increases the risk of preterm birth by approximately 153 times.

Cervical volume could be considered a new predictor for preterm birth. Moreover, its use with cervical length and uterocervical angle may bring us closer to a more successful prediction of preterm birth.