Ultrasound measurement of cervical length as predictor of threatened preterm birth: a predictive model

The incidence of preterm delivery has been increasing even in developed countries and remains a serious problem for fetuses and neonates. Although many predictors for preterm delivery have been proposed, complete prediction and prevention have not yet been established.

To examine the potential association between sonographic measurement of cervical length and threatened preterm birth (TPTB) in pregnant woman at 24-36 weeks of gestation.

A cross-sectional study included a total of 360 pregnant woman at 24-36 weeks of gestation categorized in two groups: TPTB group (n=160) and non TPTB group (n=200). The study was carried out at the Department of Obstetrics and Gynecology of the Clinical Center University of Sarajevo (KCUS). Sociodemographic and clinical characteristics of patients were obtained from medical records and physical examination by gynecologist. Transvaginal sonography was carried out by GE Voluson 730.

There was a significant association between TPTB and sonographic measurement of cervical length <25 mm (P<0.001). The logistic regression model was statistically significant, x(2)(7) = 281.530, P<0. 001. The model explained 72.6% of the variance in TPTB and correctly classified 88.1% of cases. Sensitivity was 83.8%, specificity was 91.5%, positive predictive value was 88.7% and negative predictive value was 87.6%. Out of the 7 predictor variables only 5 were statistically significant: cervical length, cervical consistency, rupture of membranes, uterine contractions and amine odor test.

The findings of this study suggest association between sonographic measurement of cervical length and TPTB.