Predicting preterm delivery in asymptomatic patients with prior preterm delivery by measurement of cervical length and phosphorylated insulin-like growth factor-binding protein-1

Authors


Abstract

Objective

To evaluate the efficacy of cervical length measurement in combination with a bedside assessment of phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1) as a predictor of preterm delivery in asymptomatic pregnant women with a history of preterm birth.

Methods

Cervical length was measured using transvaginal sonography at 22–24 weeks of gestation in 105 singleton pregnancies and a rapid strip test was performed to detect phIGFBP-1 in cervical secretions from 24 to 34 weeks. Receiver–operating characteristics (ROC) curves were constructed to compare the performance of phIGFBP-1 at different gestational ages, and cervical length at 22–24 weeks, in predicting preterm delivery.

Results

The rate of spontaneous delivery before 37 and 34 weeks was 23.8% and 11.4%, respectively. Women with cervical lengths less than 20 mm had a risk of spontaneous preterm delivery before 34 and 37 weeks of 43.5% and 69.6%, respectively. The performance of phIGFBP-1 levels as a predictor of preterm delivery was significantly higher when the test was carried out at 30 weeks' gestation. Cervical assessment in combination with phIGFBP-1 at 30 weeks had the steepest ROC curve (area under the curve = 0.93; 95% CI, 0.88–0.98, P < 0.001).

Conclusion

Both cervical length and phIGFBP-1 measurement are useful in the prediction of preterm delivery in patients with a history of preterm birth and the combined method of measuring cervical length at 22–24 weeks and phIGFBP-1 at 30 weeks improves upon either method used alone. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.

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