Fetal fibronectin (fFN) has become an important biomarker—the presence of this glycoprotein in the cervical or vaginal secretions indicates that the border between the chorion and deciduas has been disrupted. A positive test indicates an increased risk of preterm birth, and a negative test has a high predictive value.[1] It has been shown that only 1% of women in questionable cases of preterm labor delivered within the next week when the test was negative.[83]