ABSTRACT
The objective of this study was to determine if cervicovaginal fibronectin is predictive
of preterm birth. Articles involving human subjects published in English between January
1976 and December 1997 were retrieved from MEDLINE using the keywords: fibronectin,
fetal fibronectin, oncofetal fibronectin, preterm, PROM, preterm birth, and preterm
labor. We included studies that were prospective, enrolled women at less than 37 weeks'
gestation and blinded caregivers to the fetal fibronectin test results. Of the 24
studies meeting the inclusion criteria, 15 included symptomatic women; 8 included
asymptomatic women; and 1 study included both. Data were abstracted independently
by two authors and a meta-analysis of results of test characteristics, using summary
values, was undertaken where possible. For symptomatic women, the sensitivity for
delivery within 7 to 10 days of sampling was excellent (summary value [95% confidence
interval (Cl)]: 98% [95%, 100%]). For delivery within 14 days, the sensitivity was
somewhat lower (summary value [95% Cl]: 82% [74%, 90%]) and lower still for delivery
within 21 days (summary value [95% Cl]: 73% [67%, 80%]). For delivery less than 34
weeks the sensitivity was good, but poor for delivery less than 37 weeks (summary
value [95% Cl]: 87% [81%, 94%], 54% [51%, 58%] respectively). For asymptomatic women,
the sensitivity of fetal fibronectin for delivery less than 34 and less than 37 weeks
was poor (summary value [95% Cl]: 43% [36%, 50%] and 64%[57%, 71%] respectively).
The specificity of fetal fibronectin for symptomatic and asymptomatic women was over
80% for all outcomes. For symptomatic women, a negative test for fetal fibronectin
should be useful at ruling out the likelihood of delivery within 7 to 10 days of sampling.
For asymptomatic women, testing for fetal fibronectin is unlikely to be useful as
many women at risk will be misclassified as normal.
Keywords
Fetal fibronectin - preterm birth - preterm labor
