Strain Cervical Elastography in Pregnancy: Feasibility Study and Its Usefulness in Prediction of Preterm Birth

Abstract

Cervix in pregnancy is a biomechanical barrier holding the uterine contents till the time of parturition. The feasibility and reproducibility of assessing cervical tissue stiffness for predicting preterm birth by a standard method using strain cervical elastography were studied here. The prospective study included use of transvaginal strain elastography assessment of cervix at 22–24 weeks in three regions of interest: (1) Endocervical canal and entire cervix in mid-sagittal plane (2) At the level of external os in cross section and (3) at the level of internal os in cross-sectional plane, with constant pressure application each time. Strain ratios were recorded twice for the operator 1 and once by operator 2. Cervical length was also measured according to standard protocol. The measurement of strain ratios was possible in all the 85 included cases. Intra or and inter operator agreement was good for all the 3 ROIs by Kappa analysis and Pearson coefficient. In 10 cases of preterm birth with cervical length ≤ 25 mm, the strain ratios at internal os were observed to be < 1. Strain cervical elastography in pregnancy appears to be a novel, feasible and reproducible technique using a standard method for prediction of preterm birth.