The research was conducted with the use of MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov, OVID, and Cochrane Library as electronic databases from the inception of each database to February 2016. Selection criteria included randomized clinical trials of singleton gestations with threatened
preterm labor that were assigned randomly to management based on fetal
fibronectin results (ie, intervention group) or not (ie, comparison group). Types of participants included women with singleton gestations at 23 0/7 to 34 6/7 weeks with threatened
preterm labor. Studies that included management that was also based on the use of sonographic cervical length were excluded. The primary outcome was
preterm birth at <37 weeks of gestation. The summary measures were reported as relative risk or as mean differences with 95% confidence interval.
RESULTS: Six trials that included 546 singleton gestations with symptoms of
preterm labor were included in the metaanalysis. The overall risk of bias of the included trials was low. Women were eligible for the random assignment in case of symptoms that suggested
preterm labor at 23-34 weeks of gestation. During admission, before digital examination, a
Dacron swab was rotated in the posterior fornix for 10 seconds to absorb cervicovaginal secretions that were then analyzed for the fetal
fibronectin qualitative method, with results reported as either positive or negative. Women who were assigned randomly to the fetal
fibronectin group had a similar incidence of
preterm birth at <37 weeks of gestation (20.7% vs 29.2%; relative risk, 0.72; 95% confidence interval, 0.52-1.01), at <34 weeks of gestation (8.3% vs 7.9%; relative risk, 1.09; 95% confidence interval, 0.54-2.18), at <32 weeks of gestation (3.3% vs 5.6%; relative risk, 0.64; 95% confidence interval, 0.24-1.74), and at <28 weeks of gestation (1.1% vs 1.7%; relative risk, 0.74; 95% confidence interval, 0.15-3.67) compared with the control group. No differences were found in the number of women who delivered within 7 days (12.8% vs 14.5%; relative risk, 0.76; 95% confidence interval, 0.47-1.21), in the mean of gestational age at delivery (mean difference, 0.20 week; 95% confidence interval, -0.26 to 0.67), in the rate of maternal hospitalization (27.4% vs 26.9%; relative risk, 1.07; 95% confidence interval, 0.80-1.44), in the use of
tocolysis (25.3% vs 28.2%; relative risk, 0.97; 95% confidence interval, 0.75-1.24), antenatal
steroids (29.2% vs 29.2%; relative risk, 1.05; 95% confidence interval, 0.79-1.39), in the mean time in the triage unit (mean difference, 0.60 hour; 95% confidence interval, -0.03 to 1.23) and in neonatal outcomes that included
respiratory distress syndrome (1.3% vs 1.5%; relative risk, 0.91; 95% confidence interval, 0.06-14.06), and admission to the neonatal intensive care unit (19.4% vs 8.1%; relative risk, 2.48; 95% confidence interval, 0.96-6.46). Management based on the fetal
fibronectin test required higher hospitalization charges (mean difference, $153; 95% confidence interval, 24.01-281.99).
CONCLUSION: