Fetal fibronectin in patients at increased risk for premature birth

The objective of this prospective study was to evaluate fetal fibronectin bedside test (Mast Diagnostica) to rule out preterm labor.

46 patients from between 25 and 36 weeks were included in the study over a six months period. All patients underwent only one cervical sampling at the beginning of the study. The association between the fetal fibronectine test results and various outcomes were analysed.

5 of the 16 women whose test results were positive had early labor and 4 of the 30 patients with negative test results had preterm delivery. The bed side test had a sensitivity of 55.6%, a specificity of 70.3%, a positive predictive value of 31.3%, and a negative predictive value of 86.7%. The addition of tocolytic therapy and intensive care resulted probably in decrease of the predictive capacity of a positive fetal fibronectine test, odds ratio 2.95 (95% confidence interval 0.54-16.85). However interval from diagnosis to delivery was shorter (P < 0.025), cervical findings (Bishop score) worse and betamimetic treatment was more frequent (P < 0.01) in the group with positive test results.

Positive fetal fibronectine test results indicates a significant risk for the subsequent early delivery and negative test result is a good indication that subsequent preterm labor and early delivery are unlikely to occur.