Fetal fibronectin in symptomatic twin gestations

Abstract

Objective: To evaluate the negative fetal fibronectin (fFN) assay in patients with twin gestations who are symptomatic for preterm labor (PTL). Study Design: Fetal fibronectin expression in 955 symptomatic patients combined from two prospective multicenter trials was studied. Of the 955 patients, 43 had twin gestations in PTL with intact amniotic membranes at 24 and 35 weeks. Fetal fibronectin expression was evaluated in relation to delivery within 7 days of the symptomatic episode for PTL. Results: Of the 43 eligible patients, 11 had a positive fFN assay and 6 delivered ≤7 days (sensitivity 75%, positive predictive value 54.5%). Of the 32 patients who had a negative fFN, two delivered ≤7 days of testing (specificity 85.7% negative predictive value 93.7%). Conclusion: The positive predictive value of fFN among twin gestations is higher (54%) compared to singletons (12.7%), while the negative predictive value (93.7%) is comparable to singletons (99.5%). Utilizing the negative predictive value of the fFN assay may allow the clinician and patient to be reassured that delivery is unlikely to occur in the next 7 days and allow clinicians to be more conservative in their treatment of PTL in twins thereby potentially decreasing the risk of morbidity associated with these agents.