What is the primary purpose of testing fetal fibronectin (fFN) in pregnant women?

Testing for fetal fibronectin (fFN) serves the primary purpose of distinguishing between true preterm labor and false labor. Fetal fibronectin is a protein that acts as a "glue" between the fetal membranes and the maternal uterine wall. Its presence in vaginal secretions can indicate that the body is in the process of a labor event, specifically if it is detected before 22 weeks or between 24 to 34 weeks of gestation. If the fFN test is negative, it is highly predictive that preterm labor is not imminent, reducing the need for unnecessary interventions or hospitalizations. Conversely, a positive result necessitates further medical evaluation and intervention since it indicates a higher risk for preterm delivery.

In contrast, other purposes listed, such as determining fetal heart rate variability, assessing placental integrity, or evaluating maternal emotional health, are not related to the fFN test's clinical utility. Each of these areas correlates with different assessments or tests that consider distinct aspects of pregnancy and fetal monitoring, rather than the determination of true versus false labor.