Fetal fibronectin

Fetal fibronectin (fFN) is a protein that is produced during pregnancy and functions as a biological glue, attaching the amniotic sac to the lining of the uterus. It is normally detectable in vaginal secretions up until the 22nd week of gestation, after which it usually disappears until shortly before labor.

Overview

Fetal fibronectin is a high molecular weight, extracellular matrix glycoprotein, produced by amniocytes and cytotrophoblasts, that is thought to act as an adhesive between the decidua (the layer of the uterus in which the placenta is embedded) and the chorionic villi (the embryonic part of the placenta).

Clinical significance

A positive test for fetal fibronectin between the 22nd and 35th weeks of gestation can be an indication of an increased risk of preterm birth. The presence of fFN during this period can be a sign that the 'glue' is breaking down earlier than it should, which could mean that the body is preparing to give birth prematurely.

Testing

Testing for the presence of fFN is done through a vaginal swab, similar to a Pap smear. The test is non-invasive and results are usually available within a few hours. A negative result is a good sign, indicating a less than 1% chance of delivering in the next two weeks.

See also

• Preterm birth
• Pregnancy
• Protein
• Amniotic sac
• Uterus