Fetal fibronectin detection for prediction of preterm birth in low risk women

OBJECTIVE: To evaluate the clinical value of cervical fetal fibronectin detection by a quantitative enzyme-linked immunosorbent assay (ELISA) (PTDcheck, Adeza Biomedical, Sunnyvale, California, USA) as a screening tool for the prediction of preterm contractions and preterm delivery in an unselected population of pregnant women globally considered to be at low risk for preterm delivery (n = 133). DESIGN: A prospective study in which cervical fetal fibronectin samples were collected at two-week intervals between 26 and 36 weeks of gestation. SETTING: A regional training hospital. SUBJECTS: One hundred and thirty-three singleton pregnancies presenting consecutively at an antenatal clinic. MAIN OUTCOME MEASURE: Occurrence of preterm contractions and preterm delivery (delivery at < 37 weeks of gestation). RESULTS: Twenty-four (18%) patients were considered positive for the presence of fetal fibronectin. Overall 15 patients (11%) developed preterm contractions and, despite therapeutic intervention, 10 patients (8%) were delivered preterm. As a predictor for preterm contractions, cervical fetal fibronectin detection had a sensitivity of 47%, a specificity of 86%, a positive predictive value of 29% and a negative predictive value of 93%. As a predictor for preterm delivery, cervical fetal fibronectin detection had a sensitivity of 60%, a specificity of 85% a positive predictive value of 25% and a negative predictive value of 96%. CONCLUSIONS: Cervical fetal fibronectin determinations at a two-week sampling frequency for prediction of preterm birth in a general obstetric population at low risk for preterm birth has limited clinical value as a routinely performed screening procedure.