Cervical Strain Elastography in Pregnancy and Association with Maternal Factors

Purpose To assess cervical elasticity in different regions by sonoelastography, to compare the results to the Bishop score, cervical length, week of pregnancy and other maternal factors (age, weight, parity) and to evaluate the reproducibility of the method. Materials and Methods 131 patients between 17 - 41 gestational weeks were examined by transvaginal cervical strain elastography. In the sagittal view strain values were calculated in 7 regions of interest (ROI; external and internal os anterior/posterior, middle part anterior/posterior, cervical canal). In the cross sectional views strain values in 3 ROIs were evaluated at the level of the internal and external cervical os (anterior/posterior, cervical canal). The intra- and interobserver variance was tested. Results Strain values differed highly significantly in different parts of the cervix (p < 0.001). The anterior parts and the cervical canal were significantly softer with increasing gestational age and Bishop score, and the posterior parts were significantly harder with increasing maternal age, weight, parity. Cervical length showed an inverse relationship to cervical softness. The intra- and interobserver variance was low. Conclusion Elastography is a reproducible method for the evaluation of cervical elasticity in pregnancy. It showed a significant association with the Bishop score and other maternal factors and could provide additional information about changes in cervical stiffness in pregnancy.