the frequency of delivery
before 37 weeks, and the interval from sampling to
delivery for fibronectin-positive and fibronectin-negative
subjects. We calculated that 188 subjects would be
required to demonstrate a significant association between
fetal fibronectin and outcome with a positive
The primary end
points were delivery < 7 days,
predictive value of 50% and a negative predictive value
of 80%. Comparisons of fetal fibronectin were also
made to other diagnostic criteria for preterm labor
including cervical dilatation > 1 cm, contraction fi-equency,
and vaginal bleeding. Use of tocolytic medication
and mean birth weight were also compared for
fetal fibronectin positive and fetal fibronectin-negative
subjects.