Background We have previously demonstrated that women with threatened pre-term labour (PTL) who tested negative for fetal fibronectin (fFN) have a low risk of spontaneous pre-term birth (PTB) before 34 weeks gestation and reduced rates of hospital admission and corticosteroid administration.1

Aims To assess the performance of fFN 18months following its introduction to Ninewells Hospital, Dundee and to determine whether or not the initial benefits associated with fFN testing were sustained. Furthermore our aim was to assess whether or not a positive fFN test was a marker for other pathologies that might be associated with iatrogenic PTB.

Methods Data were collected prospectively from all women who presented with PTL between 01/03/10-28/02/11. Information regarding outcomes was obtained from the maternity case notes and the local maternity database.

Results 86 women had fFN testing. 12/86(14%) tested fFN-positive. 29/86(34%) required hospital admission [fFN-positive=11/12(92%) vs. fFN-negative=18/74(24%), p<0.0001]. 16/86(19.1%) received corticosteroids [fFN-positive=9/12(75%) vs. fFN-negative=7/74(9%), p<00001]. No patients received tocolysis.

8/86(9%) women delivered before 34 weeks gestation [fFN positive=4/12(33%) vs. fFN-negative=4/74(5%), p=0.01]. 2/86(2%) had spontaneous PTB before 34 weeks gestation [fFN positive=1/12(8%) vs. fFN-negative=1/74(1%), p=NS]. 6/86 (7%) had iatrogenic PTB before 34 weeks gestation [fFN positive=3/12(25%) vs. fFN-negative= 3/74(4%), p=0.03].

Conclusions In our population a negative fFN test is still associated with a low rate of spontaneous PTB before 34 weeks gestation. However a significant number of women with PTL will deliver before 34 weeks gestation for iatrogenic reasons. Our study suggests that fFN might be a marker for other pathologies associated with pre-term birth.