Fetal fibronectin testing is used in which scenario?

• A. A patient <34 weeks with regular contractions and no cervical change
• B. A patient in the second trimester for routine screening
• C. To diagnose placental previa
• D. To assess fetal lung maturity at term

Answer: (A)

Fetal fibronectin testing helps assess short-term risk of preterm delivery in symptomatic women with threatened preterm labor, typically between 24 and 34 weeks. The test looks for fetal fibronectin at the cervicovaginal interface; a negative result strongly suggests that delivery within the next week or so is unlikely, which can support avoiding unnecessary hospitalization or interventions. A positive result indicates higher risk and prompts closer monitoring and appropriate preterm management, such as corticosteroids to accelerate fetal lung maturity and, if indicated by gestational age, neuroprotection with magnesium sulfate. It’s not used for routine second-trimester screening, not for diagnosing placenta previa (that’s ultrasound), and not for assessing fetal lung maturity at term (that relies on amniotic fluid testing like the L/S ratio).