Fetal Fibronectin

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Fetal Fibronectin

Synonym/acronym: fFN.

Common use

To assist in assessing for premature labor.


Swab of vaginal secretions.

Normal findings

(Method: Immunoassay) Negative.


Fibronectin is a protein found in fetal connective tissue, amniotic fluid, and the placenta of pregnant women. Placental fetal fibronectin (fFN) is concentrated in the area where the placenta and its membranes are in contact with the uterine wall. It is first secreted early in pregnancy and is believed to help implantation of the fertilized egg to the uterus. Fibronectin is not detectable again until just before delivery, at approximately 37 wk. If it is detected in vaginal secretions at 22 to 34 wk of gestation, delivery may happen prematurely. The test is a useful marker for impending membrane rupture within 7 to 14 days if the level rises to greater than 0.05 mcg/mL.

This procedure is contraindicated for



  • Investigate signs of premature labor

Potential diagnosis

Positive findings in:

  • Premature labor (possibly initiated by mechanical or infectious processes, the membranes pull away from the uterine wall and amniotic fluid containing fFN leaks into endocervical fluid)

Critical findings


Interfering factors

  • If signs and symptoms persist in light of negative test results, repeat testing may be necessary.

Nursing Implications and Procedure


  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assess for risk of preterm delivery.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s reproductive system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Ensure that the patient knows the symptoms of premature labor, which include uterine contractions (with or without pain) lasting 20 sec or longer or increasing in frequency, menstrual-like cramping (intermittent or continuous), pelvic pressure, lower back pain that does not dissipate with a change in position, persistent diarrhea, intestinal cramps, changes in vaginal discharge, or a feeling that something is wrong.
  • The health-care provider (HCP) should be informed if contractions occur more frequently than four times per hour.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and neutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min and will be performed by an HCP specializing in this branch of medicine. Address concerns about pain related to the procedure. Explain to the patient that there should be minimal to no discomfort during the procedure.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.


  • Potential complications: N/A
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection.
  • Position the patient on the gynecological examination table with the feet up in stirrups. Drape the patient’s legs to provide privacy and to reduce chilling. Collect a small amount of vaginal secretion using a special swab from a fetal fibronectin kit.
  • Promptly transport the specimen to the laboratory for processing and analysis.


  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Recognize anxiety related to test results. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Explain the possible causes and increased risks associated with premature labor and delivery. Reinforce education on signs and symptoms of labor, as appropriate. Inform the patient that hospitalization or more frequent prenatal checks may be ordered. Other therapies may also be administered, such as antibiotics, corticosteroids, and IV tocolytics. Instruct the patient in the importance of completing the entire course of antibiotic therapy, if ordered, even if no symptoms are present. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

  • Related tests include amniotic fluid analysis (nitrazine and fern test), biopsy chorionic villus, chromosome analysis, estradiol, α1-fetoprotein, HCG, LS ratio, progesterone, and US biophysical profile obstetric.
  • Refer to the Reproductive System table at the back of the book for related tests by body system.
References in periodicals archive ?
The test is for foetal fibronectin (fFN) a protein which is detectable in a woman's cervical fluid all the way through pregnancy.
The swab test, which can be carried out from 22 weeks, looks for the presence of a protein called foetal fibronectin - a "glue-like" substance that bonds the developing baby to the uterus.
Foetal fibronectin is detectable in vaginal secretions in the very beginning of pregnancy, when the bond is first forming, and again at the end when the body is getting ready to deliver the baby.
She said she hopes to have the foetal fibronectin test if she becomes pregnant again, because it will give her extra reassurance that everything is normal.
One of the most promising developments is the foetal fibronectin test, which identifies women at high risk of premature labour by using a simple pounds 22 swab similar to a cervical smear.
When Ewena became pregnant for the second time, she was invited to take part in the Tommy's Campaign foetal fibronectin trial, a test which detects women who are at risk of going into pre-term labour.