USE OF FETAL FIBRONECTIN ASSAY AFTER TRANSVAGINAL ULTRASOUND MEASUREMENT OF CERVICAL LENGTH TO PREDICT PRETERM DELIVERY IN WOMEN WITH THREATENED PRETERM LABOR
Ahmed Mahmoud, Abdalla El Kateb, Wael Yousry
Department of Obstetrics and Gynecology, Cairo University
Objective: This study aimed to identify the value of combined transvaginal sonographic (TVS) measurement of cervical length and assessment of cervicovaginal fetal fibronectin for prediction of preterm birth in cases hospitalized for threatened preterm labor.
Materials and Methods: Seventy-five patients presenting with threatened preterm labor between 24 weeks and 34 weeks were included. TVS examination was done to determine cervical length. Fetal fibronectin concentrations of the cervicovaginal discharge were measured by ELISA technique. For prediction of preterm delivery, the cut-off value of cervical length was ≤ 25mm and of fibronectin was ≥ 50 ng/ml. The primary outcome measure was delivery before 37 weeks or within 7 days of recruitment.
Results: Sixty-six women completed the study. The proportion of preterm delivery was 37.9%. Sensitivity and specificity of fetal fibronectin were 68% and 78%, respectively and those for TVS were 72% and 65.9%, respectively. In cases with a cervical length ≤ 25 mm, fetal fibronectin ≥ 50 ng/mL showed a higher sensitivity and specificity in predicting preterm delivery before and at 37 weeks (80% and 85.7%, respectively) and within 7 days of recruitment (87.5% and 85.7%, respectively).
Conclusion: Use of fetal fibronectin assay in cervicovaginal secretions in patients having a cervix ≤ 25 mm on TVS, adds to the sensitivity and positive predictive value of fetal fibronectin testing.