The Value of Transvaginal Ultrasonographic Measurement of Cervical Length for Prediction of Preterm Delivery in Patients with Preterm Labor

Choi, Su Ran; Yang, Soon Ha; Lee, Ji Soo; Seo, Yong Soo; Kim, Jong Hwa

Abstract

OBJECTIVE
The aim of this study is to evaluate the value of vaginal ultrasonographic cervical length in prediction of preterm delivery in patients with preterm labor.
METHODS
One-hundred twenty-nine women in preterm labor at 24-34 weeks of gestation were studied retrospectively. Transvaginal ultrasonography for measurement of cervical length was performed at the time of admission. Receiver-operating characteristic (ROC) curve analysis, partial correlation coefficient, and multiple logistic regression analysis were used for statistical analysis.
RESULTS
The mean gestational age at admission was 30.2 +/- 2.5 weeks and the mean gestational age at delivery was 35.7 +/- 3.9 weeks. The median admission-to-delivery interval was 864 hours (24-2616). ROC curve analysis showed a significant relationship between cervical length and preterm delivery (area under the curve=0.82, p<0.001). The diagnostic indices of cervical length (cut-off value 2.5 cm) by ROC curve were sensitivity of 86%, specificity of 64%, and positive and negative predictive value of 54% and 90%. Multiple logistic regression analysis indicated that cervical length was an independent predictor of preterm delivery after adjustment of confounding factors (x2=0.326, p<0.01). Admission-to-delivery interval in patients with cervical length >or=2.5 cm was significantly shorter than that in patients with cervical length >2.5 cm.
CONCLUSION
Transvaginal ultrasonographic measurement of cervical length is a useful predictor of preterm delivery in patients with preterm labor and intact membranes.