Can the fetal fibronectin test be used by remote dwelling pregnant women to predict the onset of labour at term and delay transfer for birth in regional settings?

INTRODUCTION The closure of rural maternity units in Australia means an increasing number of women are transferred into major centres to await birth. Accurately excluding the onset of labour could delay relocation. The fetal fibronectin (fFN) test is used to predict preterm birth; however, the accuracy of this test for determining impending term birth is unclear. METHODS 75 women were recruited to this study from two remote maternity units. Eligibility criteria were: aged ≥18 years, singleton pregnancy, 37+0-40+3 weeks (37 weeks to 40 weeks and 3 days gestation) and no indication for induction of labour or caesarean section in next 7 days. The Quikcheck fFN® test was performed at 37 weeks and then repeated at 7 day intervals. Time-to-birth from test date was modelled using linear regression. Logistic regression models estimated odds of birth within 7 days. Separate models considered first and last test results and those at 38 weeks; adjusted for use of lubricant and gestational age. RESULTS A shorter time-to-birth was found in women with positive compared with negative fFN tests; significant at first fFN test (adjusted mean difference [AMD] 5.4 days, 95% CI 2.0-8.8) and 38 weeks (AMD 5.7 days, 95% CI 2.2-9.2 days). A positive test was also associated with a significant increase in the odds of birthing within 7 days: first fFN test adjusted odds ratio (AOR) 11.0 (95% CI 2.5-48.7), 38 weeks test AOR 14.4 (95% CI 3.4-60.2), last fFN test AOR 8.1 (95% CI 1.6-39.8). However, of women who gave birth within 7 days of testing a significant proportion had a negative fFN result; first fFN test 8/17(47.1%), 38 weeks test 4/14(28.6%) and last fFN test 29/58(50.0%). CONCLUSION The presence of fFN in cervical secretions was associated with impending term birth but its absence did not reliably exclude the onset of birth. Delaying transfer based on these findings would result in some women birthing in their home communities.