Evaluation of fetal fibronectin for threatened preterm labour in reducing inappropriate interventions.

Abstract

Preterm birth is associated with significant perinatal morbidity and mortality. The fetal fibronectin test (fFN) is used to manage women presenting with threatened preterm labour (TPTL). To evaluate the use of fFN in women presenting with TPTL with regard to hospital admission, tertiary hospital transfer and use of tocolytics and steroids in our hospital, against recommended guidelines. The ability of fFN <10ng/mL, 10-49ng/mL, 50-199ng/mL and >200ng/mL to predict outcome was also examined. This was a single-centre retrospective study from January 2015 to June 2017. All women who presented to Ipswich hospital, a level two facility for births at >32weeks of gestation, between 23 and 346 weeks of gestation with TPTL and who had fFN tests were included in the study. Fetal fibronectin <50ng/mL had a negative predictive value of 93.5% (95% CI 86.5-97.1). Despite this assurance, one in four presentations resulted in hospital admission and nearly one in ten in steroids and tocolysis administration. Birth <34weeks was 0% for fFN <10 and 2% for women with fFN levels <200ng/mL compared to nearly 30% for levels >200ng/mL. There is noncompliance with use of fFN to its full potential. This small study also provides support for the use of a 200ng/mL cut-off fFN level for birth <34weeks. This would avoid the need to transfer to a tertiary facility many women who present with TPTL.