Prediction of spontaneous preterm birth in asymptomatic twin pregnancies with the use of combined fetal fibronectin and cervical length

Objective: The purpose of this study was to evaluate combined fetal fibronectin (fFN) test result and cervical length (CL) as predictors of spontaneous preterm birth in asymptomatic twin pregnancies. Study Design: We examined a retrospective cohort of 155 twin pregnancies with combined fFN and CL testing between 22 and 32 weeks gestation. Results: A positive fFN test result at 22-32 weeks or a CL <20 mm increased the risk of spontaneous preterm birth at <37, <34, <32, <30, and <28 weeks' gestation. The combination of a positive fFN test result and CL<20 mm had a significantly higher positive predictive value for delivery at all gestational ages than either positive test alone. On adjusted analysis, a positive fFN test result was a stronger predictor of spontaneous preterm birth than a short CL. Conclusion: In asymptomatic twin pregnancies, fFN and CL testing between 22 and 32 weeks gestation can identify pregnancies that are at significantly increased risk for preterm birth, including deliveries at <28 weeks' gestation.