Is dynamic cervical shortening during symptomatic contractions predictive of preterm delivery in patients with a normal baseline cervical length?

OBJECTIVE

The purpose of this study was to determine whether dynamic cervical change in symptomatic patients with a normal baseline cervical length (CL; >or=30 mm) is predictive of preterm delivery (PTD).

METHODS

A prospective observational study was performed in 120 symptomatic patients between 23 and 34 weeks' gestation. Patients underwent standardized CL sonography with contraction monitoring, and CL measurements were recorded each minute for approximately 10 minutes. Initial and minimum CLs as well as the presence of dynamic change were assessed for prediction of PTD.

RESULTS

Forty-seven patients (39.2%) had dynamic cervical change and delivered at a mean gestational age +/- SD of 37.1 +/- 2.7 weeks compared to 38.7 +/- 1.5 weeks for those without dynamic change (P < .01). A larger proportion of those with dynamic change delivered before 37 weeks (43% versus 15%; P < .01) and before 35 weeks (19% versus 0%; P < .01). Multivariable logistic regression analysis showed that dynamic cervical change was predictive of PTD, but not independently of the minimum CL. Statistical analyses were completed using the Student t test, chi(2) test, Fisher exact test, Wilcoxon rank sum test. and logistic regression as appropriate.

CONCLUSIONS

Although symptomatic patients with a normal baseline CL who have dynamic shortening generally deliver at term, they appear to be at increased risk of PTD.