Fetal fibronectin (fFN) is a protein produced during pregnancy that acts as a "biological glue," helping to attach the fetal sac to the uterine lining. This protein is typically found in the amniotic fluid and the interface between the maternal and fetal tissues. Under normal circumstances, fetal fibronectin is not present in significant amounts in vaginal secretions between weeks 22 and 35 of pregnancy.
