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

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

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.

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.

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.