Fetal Fibronectin and Ultrasonographic Examination of Cervix: Which is Better as a Predictor of Preterm Delivery in Patients with Preterm Labor and Intact Membranes?

Yang, S H; Roh, J R; Jeong, J H

Abstract

OBJECTIVE
The purpose of this study was to compare the diagnostic performance of fetal fibronectin and ultrasonographic examination of the cervix in the prediction of preterm delivery in patients with preterm labor and intact membranes. Study DESIGN: Fifty-one women of singleton pregnancy admitted with preterm labor (22 to 35 weeks) and cervical dilation < 3 cm were included in this study. Endovaginal ultrasonography of uterine cervix and qualitative assay of fetal fibronectin in cervicovaginal secretion were performed at the time of admission. Cervical parameters evaluated included endocervical length, presence of funneling, funnel length, and funnel width. Cervicovaginal fetal fibronectin was determined by immunoassay kit using fetal fibronectin-specific monoclonal antibody FDC-6 (ROM-CheckR, Adeza Biochemical, U.S.A). Outcome variables were preterm delivery before the 36th week of gestation, preterm delivery before the 34th week of gestation and admission-to-delivery interval.
RESULTS
The prevalence of preterm pregnancy was 35.4% (18/51). The diagnostic indices of fetal fibronectin and ultrasonographic examination of the cevix (cervical length < or =2.6cm and presence of funneling), considered separately, were approximately equivalent in predicting delivery before 34th week of gestation and delivery before 36th week of gestation. Combining fetal fibronectin and cervical length < or =2.6cm did not improve positive predictive value. Patients with positve fetal fibronectin, cervical length < or =2.6cm, or presence of funneling resulted in shorter admission-to-delivery interval.
CONCLUSION
Both of fetal fibronectin and cervical ultrasonographic examination are useful predictors of preterm delivery in patients with preterm labor and intact membranes. For physicians equipped to perform transvaginal ultrasonography, however, the additional information about the result of fetal fibronectin provides little benefits.