Repeat Measurement of Cervical Length in Women with Threatened Preterm Labor.

Abstract

To examine the value of a repeat measurement some days after the first cervical length measurement done at the time of preterm contractions. Retrospective study involving women with singleton pregnancies who presented with preterm contractions at 24 to 33 + 6 weeks of gestation. The cervical length was measured at the time of presentation and some days afterwards. The study population consisted of 17 cases with a preterm delivery within 14 days and 288 uneventful pregnancies. Univariate logistic regression analysis indicated a significant correlation between delivery within 14 days and both, the first and second cervical length measurements as well as the difference between the two measurements. Up to a false positive rate of 20 %, ROC curve analysis showed an improved detection rate for preterm delivery by inluding both measurements. At a false positive rate of 10 % - which corresponds to a first and second cervical length of 10 and 9 mm - the detection rate was 17.6 % with the first cervical length measurement, 47.0 % with the second and 52.9 % if the difference between both measurements was added. Our results indicate that in women with symptoms of preterm labor it is worth to repeat the measurement some days later and to take into account the difference between both measurements.