A screening test that identifies the probability of preterm labor. Fibronectin, a cold insoluble globulin, is usually found in cervicovaginal fluid during the first 20 weeks of pregnancy. It is then undetectable until about gestational week 34. A positive fFN test result in women with symptoms of threatened preterm labor indicates the probability of delivery within 1 week. Aggressive treatment of threatened preterm labor with tocolytics and corticosteroids increases potential for fetal survival.