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Evaluation of a quantitative fetal fibronectin test for spontaneous preterm birth in symptomatic women

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Original languageEnglish
Article numberN/A
Pages (from-to)122.e1-122.e6
Number of pages6
JournalAmerican Journal of Obstetrics and Gynecology
Issue number2
PublishedFeb 2013

King's Authors


The purpose of this study was to determine whether quantification of cervicovaginal fluid fetal fibronectin (fFN) improves diagnostic accuracy of spontaneous preterm birth (sPTB) in symptomatic women.

Study Design
A prospective blinded predefined secondary analysis of a larger study of cervicovaginal fluid fFN concentration (nanograms per milliliter) in women symptomatic of preterm labor (n =300 women; 22-35 weeks' gestation) with a Hologic 10Q system (Hologic, Marlborough, MA). Clinicians were blinded to the result until after the delivery, but the qualitative Hologic TLIIQ fFN result was made available.

The positive predictive value for sPTB (<34 weeks' gestation) increased from 19%, 32%, 61%, and 75% with increasing thresholds (10, 50, 200, and 500 ng/mL, respectively). Compared with <10 ng/mL fFN, the relative risk of delivery was 5.6 (95% confidence interval [CI], 1.05–29.57), 7.9 (95% CI, 1.38–45.0), 22.8 (95% CI, 3.84–135.5), and 51.3 (95% CI, 12.49–211.2; P < .01).

Quantitative fFN provides thresholds (10 and 200 ng/mL) in addition to the qualitative method (50 ng/mL) to discriminate the risk of sPTB in symptomatic women.

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