Fetal Fibronectin

Does this test have other names?

fFN

What is this test?

This test measures the amount of fetal fibronectin (fFN). Fetal fibronectin 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 may help you 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 when uterine contractions increase.

Why do you need this test?

You may need this test if you are at risk of delivering your baby prematurely. Your doctor may order this test if you are 22 to 35 weeks pregnant and 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 doctor may also order this test if you don't have symptoms but have a history of preterm labor or if you have a short cervix. 

What other tests might you have along with this test?

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

What do your test results mean?

Test results may vary depending on your age, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your doctor what your test results mean for you.

Your doctor 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 doctor 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 needs a sample of cervical fluid and is much like a Pap test. Your doctor will put a speculum in your vagina. They will take a swab of cervical fluid from the area just outside the opening of your cervix or from the back side of the vagina.

Does this test pose any risks?

This test poses no known risks.

What might affect your test results?

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

How do you get ready for this test?

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

Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.