OBJECTIVE: To test a sequential test with fetal fibronectin detection after ultrasound measurement of cervical length to predict preterm delivery in women with preterm labor. STUDY DESIGN: Descriptive retrospective study on 111 women hospitalised for preterm labor between 24 and 34 weeks and six days of gestation. The primary outcomes were preterm delivery before 34 or 37 weeks of gestation or within seven or 14 days. Selective use of fetal fibronectin detection after cervical length measurement has been tested, with a sequential test considered positive if cervical length was inferior or equal to 15 mm or if cervical length was between 16 and 30 mm with fetal fibronectin positive. RESULTS: The sensitivity/specificity/and positive and negative predictive values of fetal fibronectin positive were 75, 71, 17 and 97% for delivery within 14 days; those of cervical length inferior or equal to 20mm were 75, 52, 21, and 92% for delivery before 34 weeks. The efficiency of the sequential test was similar with excellent negative predictive value: sensitivity/specificity/and positive and negative predictive values of 75, 63, 26, and 93.5% for prediction of preterm delivery before 34 entire weeks. The use of this sequential test could have avoided 37% of fibronectin tests. CONCLUSION: A sequential test with selective use of fetal fibronectin detection in population selected by ultrasound measurement of cervical length appears to be as effective than fetal fibronectin detection or cervical length alone for predicting preterm birth, if preterm labor, avoiding more than one third of fibronectin tests.
OBJECTIVE: To test a sequential test with fetal fibronectin detection after ultrasound measurement of cervical length to predict preterm delivery in women with preterm labor. STUDY DESIGN: Descriptive retrospective study on 111 women hospitalised for preterm labor between 24 and 34 weeks and six days of gestation. The primary outcomes were preterm delivery before 34 or 37 weeks of gestation or within seven or 14 days. Selective use of fetal fibronectin detection after cervical length measurement has been tested, with a sequential test considered positive if cervical length was inferior or equal to 15 mm or if cervical length was between 16 and 30 mm with fetal fibronectin positive. RESULTS: The sensitivity/specificity/and positive and negative predictive values of fetal fibronectin positive were 75, 71, 17 and 97% for delivery within 14 days; those of cervical length inferior or equal to 20mm were 75, 52, 21, and 92% for delivery before 34 weeks. The efficiency of the sequential test was similar with excellent negative predictive value: sensitivity/specificity/and positive and negative predictive values of 75, 63, 26, and 93.5% for prediction of preterm delivery before 34 entire weeks. The use of this sequential test could have avoided 37% of fibronectin tests. CONCLUSION: A sequential test with selective use of fetal fibronectin detection in population selected by ultrasound measurement of cervical length appears to be as effective than fetal fibronectin detection or cervical length alone for predicting preterm birth, if preterm labor, avoiding more than one third of fibronectin tests.