Health Encyclopedia

Fetal Fibronectin

Does this test have other names?


What is this test?

This test measures the amount of fetal fibronectin (FFN). FFN is a protein made during pregnancy. It's found between the lining of your uterus and the amniotic sac that's protecting your baby. Fetal fibronectin works as a glue to hold the amniotic sac to the uterine lining.

This test helps find out whether you're at risk for premature delivery. The protein is found in cervical and vaginal fluid during the first half of your pregnancy and then disappears. It should reappear only in the last month before you deliver. 

Why do I need this test?

Your healthcare provider may order this test if you are at risk of delivering your baby prematurely. Your provider may order this test if you have any symptoms of premature labor. These include:

  • Pelvic pressure or cramping

  • Dull low backache

  • Uterine contractions every 10 minutes or more often

  • Change in vaginal discharge

  • Thinning or dilation of the cervix

Your provider may also order this test if you don't have symptoms but you have a history of preterm labor or if you have a short cervix. 

What other tests might I have along with this test?

Your healthcare provider may also order a vaginal ultrasound if you test positive for FFN but don't have signs of labor.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

Your provider will report your results as either positive or negative. Positive means FFN is present. Negative means FFN isn't present.

If you test positive but have no signs of labor, you may be at risk for both premature labor and premature delivery. If you test positive and you have symptoms of premature labor, your healthcare provider will want to watch you closely.

A negative test result means you're not likely to go into labor within the next 2 weeks. 

How is this test done?

The test requires a sample of cervical fluid and is much like a Pap test. Your healthcare provider will put a speculum in your vagina. He or she will take a swab of cervical fluid from the area just outside the opening of your cervix.

Does this test pose any risks?

This test poses no known risks.

What might affect my test results?

Your test results may be affected by a yeast infection, using lubricants or douches, or having had sex within 24 hours of the test. Certain health conditions and certain medicines may cause extra bleeding.

How do I get ready for this test?

You don't need to prepare for this test. But you should avoid having sex within 24 hours of the test. Also avoid putting anything, such as lubricants or douches, into your vagina before the test.


Medical Reviewers:

  • Hanrahan, John, MD
  • Sather, Rita, RN