Aims To assess the ability of fetal fibronectin (fFN) in predicting pre-term birth (PTB) in Ninewells Hospital, Dundee. More specifically, to determine the rate and duration of maternal admission in women that presented with threatened pre-term labour who had fFN. Furthermore our aim was to assess whether or not these women received corticosteroids and tocolysis and assess pregnancy outcomes.

Methods Data was collected prospectively from all women who presented with threatened pre-term labour between 1 September 2009 and 28 February 2010. Information regarding delivery outcomes was obtained from the maternity case notes and the local maternity database.

Results 40 women had fFN testing. 6/40 (15%) tested fFN-positive. 17/40 (42.5%) were admitted (fFN-positive=6/6 (100%) vs fFN-negative=10/34 (29%)) (p=0.002). The mean duration of admission was 2 days (fFN-positive=2.5 days vs fFN-negative=1.7 days) (p=ns). 9/40 (22.5%) received corticosteroids (fFN-positive=5/6 (83%) vs fFN-negative=4/34 (12%)) (p=0.001). No patients received tocolysis.

8/40(20%) had spontaneous PTB before 37 weeks gestation (fFN positive=5/6(83%) vs fFN-negative=3/34 (9%)) (p=0.0005). In our population fFN has a sensitivity of 62.5% and a specificity of 100% for predicting spontaneous PTB before 37 weeks gestation (positive predictive value=83%, likelihood ratio=5, negative predictive value=91%, LR=0.09).

Conclusions In our population the majority of women who present with threatened pre-term labour will deliver at term. A positive fFN test is a moderate predictor of spontaneous PTB before 37 weeks gestation. However a negative fFN test is a strong predictor that spontaneous PTB before 37 weeks gestation will not occur. A negative fFN test can reassure women and prevent interventions such as hospital admission and the administration of corticosteroids.