FETAL FIBRONECTIN IN PATIENTS AT INCREASED RISK FOR PREMATURE BIRTH

OBJECTIVE: The objective of this study was to evaluate fetal fibronect in as a screening test for subsequent preterm birth in asymptomatic pr egnant women. STUDY DESIGN: Eighty-seven pregnant women at increased r isk for preterm birth underwent weekly sampling of cervicovaginal secr etions beginning in the middle of the second trimester and continuing until delivery or until 34 weeks of gestation, with quantitative measu rement for fetal fibronectin. In addition, assessment of cervical dila tation, uterine activity, and tocolytic therapy was performed with eac h sampling. Preterm birth was the specific outcome measured, and the c orrelation of fetal fibronectin with this outcome was determined. RESU LTS: Overall, 31% of the patients experienced a spontaneous preterm bi rth. As a predictor for delivery before 37 completed weeks of gestatio n, the presence of fetal fibronectin had a sensitivity of 92.6%, a spe cificity of 51.7%, a positive predictive value of 46.3%, and a negativ e predictive Value of 93.9%. For delivery before 34 weeks, fetal fibro nectin had a sensitivity of 92.3% and a negative predictive value of 9 7.8%. By means of logistic regression analysis a positive fetal fibron ectin result was highly significantly correlated with preterm birth (o dds ratio 3.8, p < 0.001) and more so than the presence of four or mor e uterine contractions per hour, tocolytic therapy or cervical dilatat ion of greater than or equal to 2 cm. The addition of contractions, to colytic therapy, or cervical dilatation to a positive fetal fibronecti n result did not increase the predictive capacity of a positive fetal frbronectin alone. CONCLUSION: Fetal fibronectin in the cervicovaginal secretions of asymptomatic patients has potential value as a screenin g test in the identification of patients at risk for preterm birth. Th is test had equally high sensitivity and negative predictive value for birth before 37 weeks.