Myometrial elasticity determined by elastosonography to predict preterm labor

To determine the utility of elastosonography (ES) combined to cervical length measurement to predict preterm labor.

One hundred twenty-seven women with pregnancies between 21 to 36 weeks of gestation without any risk factor for preterm labor were included in the study. All subjects underwent sonographic evaluation including fetal biometry, cervical length measurement and ES of uterine myometrium. Subcutaneous tissue was the reference point for ES evaluation. Tissue strain ratio values were obtained from all patients.

Cervical length was a significant predictor for preterm delivery (AUC = 0.958, p < 0.001). Optimal cut-off value was obtained at 30 mm with 92% sensitivity and 81% specificity. Elastosonographic strain ratio was also a significant predictor for preterm delivery (AUC = 0.827, p < 0.001). Optimal cut-off value was obtained at 4.7 with 79% sensitivity and 91% specificity. In linear regression analysis, strain ratio (R(2 )= 0.61, beta = 0.171, p = 0.03) and cervical length (R(2 )= 0.61, beta = -0.516, p < 0.001) were significantly associated with preterm delivery. Cervical length < 30 mm [39.1 (95 CI, 6.6-231.5, p < 0.001)] and strain ratio > 4.7 [24.5 (95 CI, 4.1-146.5, p < 0.001)] were the risk factors for preterm delivery.

Elastosonographic evaluation of uterine myometrium was found to be significantly correlated with cervical length but cervical length measurement is a better predictor for preterm labor than ES.