Final answer:
The Fetal Fibronectin test is used to assess the risk of preterm labor by detecting the presence of fibronectin in the cervico-vaginal fluid of pregnant women.
Step-by-step explanation:
The theory behind the Fetal Fibronectin test in a case of suspected preterm labor is based on the detection of a protein called fibronectin in the cervico-vaginal fluid of pregnant women. Fibronectin is normally found in high amounts in the cervix, but its presence in the vaginal fluid may indicate that the cervix is undergoing changes that could lead to preterm labor. By measuring the levels of fibronectin, healthcare professionals can assess the risk of preterm labor and take appropriate measures to manage the pregnancy.