More information

We know the possibility of preterm birth can be confusing and concerning. The curated content below can provide further answers about preterm birth, fFN testing and more to support you during your pregnancy.

Frequently asked questions

What is fetal fibronectin testing?

  • Fetal fibronectin (also known as fFN) is a “glue-like” protein that bonds the baby to the uterus.
  • fFN holds the baby in place during its development, and fFN is usually not detectable in vaginal secretions during weeks 16 to 35 of gestation.1
  • If fFN is leaking into the vagina and detectable in vaginal secretions during this time period, this can be a sign that your body is preparing to deliver early.2

Will I be able to feel it if I am leaking fetal fibronectin (fFN)?

No, fFN leaks in tiny nanograms invisible to the naked eye. You will not be able to tell if you are leaking fetal fibronectin. Your physician also will not be able to tell just by examining you, which is why he or she will use the Rapid fFN® test to determine whether you are leaking fFN and are at an increased risk for preterm labor.

Why is knowing my Rapid fFN® test result important?2

  • Approximately 20% of women will get a positive Rapid fFN® test result. A positive result does not necessarily mean you will deliver soon, but a positive result will alert your doctor to the fact that you are at a higher risk of a preterm birth.
  • A negative test result, on the other hand, can provide great peace of mind, because a negative test result means you have less than a 1% chance of giving birth in the next 14 days.

Is the Rapid fFN® test FDA-approved?

  • fFN testing is FDA approved in symptomatic patients between 240and 346 weeks gestation. The FDA has also approved fFN testing for asymptomatic patients at risk of preterm delivery between 220 and 306 weeks gestation.2

Where is the Rapid fFN® test used?

The Rapid fFN® test is used in over 2,000 birthing hospitals across the United States.3

Are there any side effects with the Rapid fFN® test?

No, the test is done much like a Pap test. It’s non-invasive, and there are no related side-effects for you or your baby.2

Can I get tested more than once?

Yes. You and your doctor can decide to repeat the test as often as every 2 weeks during weeks 22 to 35 of gestation.2

I’m pregnant with twins, can the Rapid fFN® test be used on patients with a twin pregnancy?

Yes, the Rapid fFN® test is approved for use in both singleton and twin pregnancies.2

Women and wellness resources


A weekly internet radio show for and by women immersed in the fullness of motherhood…



A support community for new moms and moms-to-be, with resources such as blogs, bulletin boards,…


Preterm delivery support groups

March of Dimes

Aims to improve the health of babies by preventing birth defects, premature birth, and infant…


Tommy’s (UK)

Believes every baby deserves the best start in life. Tommy’s funds research and provides information…



For women (and their families) experiencing complicated pregnancies. The site gives visitors access to an…


Pregnancy resources


The pregnancy section of WebMD provides community views and insights.

Talk to your doctor

Download our Rapid fFN® test discussion guide to help you and your doctor determine the right choice when assessing your risk of preterm birth.

Talk to your doctor

Download our Rapid fFN® test discussion guide to help you and your doctor determine the right choice when assessing your risk of preterm birth.