fFN (fetal fibronectin) test

Starting at: 22 weeks or earlier if possible
Frequency: Every 2 weeks until 36 weeks
Purpose: To determine the risk of preterm delivery.

Fetal fibronectin (fFN) is a protein produced in pregnancy that functions as a “glue” attaching the amniotic sac to the uterine lining. The fFN test measures the amount of fetal fibronectin in vaginal secretions and is performed like a pap smear test. A determination that the fFN “glue” is disintegrating may be a sign that a woman is at risk for preterm delivery, even if she is otherwise asymptomatic.

The fFN test is most useful in ruling out preterm delivery, rather than predicting it. In other words, a negative fFN test is a reliable predictor that delivery will not occur in the next 2 weeks, but a positive fFN test does not necessarily indicate that preterm delivery is imminent.

Most health care practitioners will not order an fFN test before 22 weeks since it is normal for there to be some fFN in the vaginal fluids up until then. If you are asymptomatic, your practitioner may not order repeat testing. Also, your health insurance may not cover initial or repeat testing if you are not showing any other signs of preterm delivery. For more information about the fFN test, seeĀ www.ffntest.com.

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