Clinical utility of fetal fibronectin for predicting preterm birth

To determine if fetal fibronectin can be used in a clinical setting to predict preterm birth and guide clinical management.

We implemented a clinical protocol using the rapid fetal fibronectin test for patients presenting with symptoms of preterm labor. Adherence to the clinical pathway was at the discretion of the practitioner. Subjects who met the inclusion criteria (n = 404) were divided into 2 groups based on the fetal fibronectin result. Outcomes included time until delivery, gestational age at delivery and use of therapeutic interventions. Univariate and multivariate statistical analyses were performed.

The 46 subjects (11.4%) with positive fetal fibronectin were more likely to deliver within 7 days, within 14 days, prior to 32 weeks' gestation and prior to 37 weeks' gestation (RR 22.0, 22.0, 12.3 and 5.1, respectively). For delivery within 7 days, the sensitivity, specificity, positive predictive value and negative predictive value were 67%, 92%, 30% and 98%, respectively. Time until delivery and gestational age at delivery were lower in women with a positive test, while the frequency of therapeutic interventions was higher (p < 0.01).

A positive fetal fibronectin test is predictive of preterm birth in a clinical setting. A negative fetal fibronectin test can be used to avoid unnecessary, potentially harmful interventions.