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Fetal Fibronectin Testing in Threatened Preterm Labor


Am Fam Physician. 2020 Aug 1;102(3):145-146.


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No preterm deliveries were prevented

No increase in maternal hospitalizations



No preterm deliveries were prevented

No increase in maternal hospitalizations

Study Population: Women with singleton pregnancies and threatened preterm labor undergoing fetal fibronectin testing between 23 and 35 weeks' gestation

Efficacy End Points: Reduction in preterm deliveries at less than 37 weeks, less than 34 weeks, and less than 32 weeks

Harm End Points: Increase in maternal hospitalization

Narrative: In the United States, approximately 9.6% of live births are preterm (before 37 weeks). This rate has been declining due to increased effort to reduce non–medically indicated deliveries before 39 weeks' gestation.1 Hospitalization of infants after preterm birth may cost as much as $5.8 billion annually, representing approximately one-half of the costs for all infant hospitalizations in the United States.2 Because many women who present with threatened preterm labor symptoms deliver at term, identifying the subset of women with preterm labor symptoms who will have a preterm delivery would be useful. Fetal fibronectin testing is a common clinical test, performed via cervicovaginal secretion swab after 22 weeks of pregnancy, and is used to identify women at increased risk for preterm delivery. One national claims database study found that 12% of patients presenting with threatened preterm labor symptoms had fetal fibronectin testing performed in the emergency department or the emergency labor and delivery unit.3 Guidelines from the American College of Obstetricians and Gynecologists do not recommend the use of fetal fibronectin testing alone to guide the management of acute patients.4

The Cochrane review discussed here included six randomized controlled trials with a total of 546 women with singleton pregnancies and

Author disclosure: No relevant financial affiliations.


show all references

1. Hamilton BE, Martin JA, Osterman MJ, et al. Births: final data for 2014. Natl Vital Stat Rep. 2015;64(12):1–64....

2. Russell RB, Green NS, Steiner CA, et al. Cost of hospitalization for preterm and low birth weight infants in the United States. Pediatrics. 2007;120(1):e1–9.

3. Blackwell SC, Sullivan EM, Petrilla AA, et al. Utilization of fetal fibronectin testing and pregnancy outcomes among women with symptoms of preterm labor. Clinicoecon Outcomes Res. 2017;9:585–594.

4. Practice Bulletin No. 171 Summary: management of preterm labor. Obstet Gynecol. 2016;128(4):931–933.

5. Berghella V, Saccone G. Fetal fibronectin testing for reducing the risk of preterm birth. Cochrane Database Syst Rev. 2019;(7):CD006843.



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