The fetal fibronectin (fFN) test can help predict if a woman will go into labor early. fFN is a protein found in the amniotic sac and fetal membranes during the first 22 weeks of pregnancy. If a doctor believes a woman is going into premature labor, he or she can test the woman's cervical-vaginal secretions; if fFN is present after 22 weeks, it indicates increased risk for preterm delivery. If it is absent, the risk is low and the woman probably won't deliver in the next 2 weeks.
The test is performed like a Pap smear. A swab of cervical-vaginal secretions is taken from the top of the vagina, behind the cervix. Results are available from the lab within 24 hours.