Uterocervical angle versus cervical length in the prediction of spontaneous preterm birth in singleton pregnancy

Abstract

Objective: To evaluate the predictive role of the uterocervical angle and the cervical length in preterm birth.

Methods: This was cross-sectional analytical study, recruiting 167 women at high-risk for preterm birth (delivery before 37 weeks of pregnancy). They had transvaginal ultrasound for evaluation of the uterocervical angle and the cervical length between at 30 and 32, 32⁺¹ and 34, and 34⁺¹ and 36⁺¹ weeks of pregnancy. The primary outcome was to determine the predictive role of the uterocervical angle and the cervical length in preterm birth.

Results: The mean uterocervical angle was significantly greater in those who delivered preterm (115.4° ± 9.1° versus 101.1° ± 8.3°, p < 0.001). The cervical length was insignificantly shorter in the same group (27.9 ± 4.0 and 29.1 ± 4.1 mm, respectively, p = 0.067). A uterocervical angle of 105° or more predicted preterm birth with sensitivity and specificity of 86.1% and 60.4%, respectively. A cervical length of 25 mm or less had sensitivity and specificity of 27.8% and 85.8%, respectively.

Conclusion: A uterocervical angle greater than 105° poses a high risk for preterm deliveries. It provides a higher diagnostic performance in high-risk patients than cervical canal length measurement.

Keywords: cervical angle; cervical length; pregnancy; preterm birth; ultrasound.