Fetal fibronectin as a predictor of preterm delivery in twin gestations.

OBJECTIVE: To evaluate fetal fibronectin as a predictor of premature delivery in twin pregnancies. METHOD: Cervicovaginal secretions were obtained from 52 pregnant women with twin pregnancies between 24 and 34 weeks of gestation. The secretions were analyzed to detect the presence of fetal fibronectin by immediate-reading membrane test. The correlation between the presence of fetal fibronectin and preterm birth was evaluated. In addition, cervical dilatation and effacement were evaluated with each sampling. RESULT: The sensitivity, specificity, positive predictive value and negative predictive value to predict preterm delivery were 89.3, 50.0, 67.6, and 80.0%, respectively. A positive fetal fibronectin result was associated with a relative risk (RR) for preterm birth of 3.4 (95% CI, 1.2-9.5). A positive fetal fibronectin test associated with cervical dilatation or effacement increased the RR for preterm birth to 4.3 and 7.7, respectively, when compared with those with negative test and without cervical dilatation and effacement. CONCLUSION: Fetal fibronectin in the cervicovaginal secretions of patients with twin pregnancies is a sensitive predictor of preterm delivery. However, because of its low specificity, the fetal fibronectin test should be evaluated along with cervical changes for better identification of twins likely to develop preterm labor.