Ultrasonographic Evaluation of Cervical Length, Cervical Volume and Cervical Vascularization between 18 and 40 Weeks of Gestation

Abstract

Objective: To evaluate the correlation of cervical length, cervical volume and cervical vascularization during pregnancy using 3D power Doppler ultrasonography, and to examine the reliability of these measurements.
Methods: This is a cross-sectional study of 196 pregnant women who delivered at term and had undergone transvaginal 3D power Doppler ultrasonographic examination of the cervix once between 18 and 40 weeks’ gestation. Cervical length, cervical volume, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were measured and calculated. The reliability of the measurements was also evaluated.
Results: Mean cervical length and volume were 35.2 mm. and 28.2 cm³. Mean cervical VI, FI and VFI were 2.65, 38.44 and 1.07, respectively. Cervical length and cervical volume significantly decreased during pregnancy (Spearman’s rank correlation coefficient, Rho = -0.422 and -0.514, respectively, correlation significant <0.01). There was a minimal change in the vascular flow indices between 18 and 40 weeks’ gestation (Spearman’s rank correlation coefficient, Rho, varied from 0.010 to 0.042). Both intraobserver and interobserver agreement for cervical volume measurements were excellent with intraclass correlation coefficient (ICC) values of 0.96, and 0.95 respectively. Intraobserver and interobserver agreement for vascular flow indices measurements were good.
Conclusion: Cervical length and volume significantly decreased with gestational age. Cervical vascularization tends to be increased, but without statistical significance. The measurements were reliable.