Measurement of the uterocervical angle for the prediction of preterm birth in symptomatic women

Purpose To examine if the uterocervical angle (UCA) can be used to predict preterm delivery in women with painful and regular uterine contractions and a cervical length of 25 mm or less. Methods Retrospective study at the perinatal unit of the University Hospital of Tuebingen, Germany. Women with singleton gestation and preterm contractions between 24 + 0 and 33 + 6 weeks' gestation were included. For the UCA measurement, a line is placed from the internal os to the external os irrespective of whether the cervix is straight or curved. A second line is drawn to delineate the lower uterine segment. The angle between the two lines is the UCA measurement. The measurements were taken on stored images from our database. Results The study consisted of 213 singleton pregnancies. At the time of UCA measurement, median maternal and gestational age was 31.4 years and 29.7 weeks' gestation. Median gestational age at delivery was 35.3 weeks and the corresponding birth weight 2480 g, respectively. The UCA measurement in women who delivered within 2 days, between 3-7 days and after 7 days was not helpful to distinguish between these three groups [median UCA measurements: 108.5 degrees, 108.0 degrees and 107.3 degrees (Kruskal-Wallis test p = 0.576)]. Uni- and multivariate logistic multiple regression analysis demonstrated that the delivery within 2 days was only dependent on the gestational age and the cervical length at the time of presentation. Conclusion The measurement of UCA is not useful in predicting preterm birth in the subsequent 7 days after an episode of preterm contractions.