Uterocervical angle at 20 weeks: A promising predictor of spontaneous preterm birth in twin pregnancies

Objective: To compare the performance of uterocervical angle (UCA) and cervical length (CL) measurement at 20 weeks of pregnancy for prediction of spontaneous preterm birth (sPTB) in twin pregnancies.

Study design: We conducted a retrospective cohort study of 424 twin pregnancies who delivered in our center from October 2014 to December 2018 and who underwent transvaginal ultrasound between 19⁺⁰-22⁺⁰ weeks to measure CL during routine second trimester scan. Recorded ultrasound images of CL were reassessed to evaluate UCA. Medical and obstetric data were also collected for statistical analysis.

Results: A total of 424 women were included. The rates of sPTB rate below 28, 32 and 34 weeks of gestation were 2.8 %, 5.4 % and 10.4 %, respectively. ROC curves showed a better area under the curve (AUC) for UCA at all gestational ages compared with CL (AUC for sPTB <28 weeks 0.902 (p < 0.001) vs 0.620 (p 0.175); AUC for sPTB <32 weeks 0.740 (p 0.001) vs 0.620 (p 0.058); AUC for sPTB <34 weeks 0.676 (p 0.001) vs 0.632 (p 0.047). UCA > 120 degrees was significantly associated with sPTB <28 weeks (p < 0.001; OR 39.17; CI 4.81-319.23; NPV, 99.65 %), <32 weeks (OR 4.23; p 0.002) and <34 weeks of gestation (OR 2.66; p 0.01).

Conclusion: In our study, an UCA > 120 degrees allowed to identify those women with twin pregnancies at risk of sPTB and performed better than CL measurement.