Sonographic Cervical Markers at the Second Trimester for the Prediction of Preterm Birth

Background: This study aimed to assess the diagnostic value of novel ultrasonographic markers, Anterior Uterocervical Angle (AUA), Cervical Consistency Index (CCI) and Cervical Glandular Area (CGA) in the Prediction of Preterm Birth (PTB), in a general population. Methods: We conducted a prospective cohort study on singleton gestations between 16 -24 weeks undergoing transvaginal sonography for Cervical Length (CL) screening. AUA, CCI and CGA were evaluated. The primary outcome was prediction of spontaneous PTB before 37 weeks’ gestation by UCA, CCI and CGA. The secondary outcome was evaluating performance of these markers alone and in combination with CL to predict PTB. Results: A total of 310 women were studied. The rate of PTB in this population was 10.6 % for delivery before 37 weeks. In the PTB group, the shorter CL, the wider AUA and the lower CCI were significant, but the CGA width and area were not significantly different in term and PTB groups. The optimal cut-off based on the ROC curve was 33.15 mm for CL (sensitivity: 57%; specificity: 68%), 102.5 degrees for AUA (sensitivity: 50%; specificity: 80%), and 60.3% for CCI (sensitivity: 43%; specificity: 68%). Conclusions: Our data indicate that the combination of CL and CCI (positive likelihood ratio:3; negative likelihood ratio:0.7) and the combination of CL and AUA (positive likelihood ratio:4.8; negative likelihood ratio:0.76) are better methods for the prediction of spontaneous PTB before 37 weeks; and can be used as a screening tool in the second trimester.