Abstract:ObjectiveTo determine the predictive value of fetal fibronectin alone or combined with Cervical length(CL)for preterm birth in pregnant women witn preterm labor.Methods Pregnant women were collected from Obstetrics clinics of Baogang trird hospital.We measured the fFN level and the CL,and followed up the pregnant outcomes.ResultsAmang 150 subjects,positive fFN was detected in 24.67%(37/150)；The prevalence of spontaneous pretem delivery among those women with positive fFN was with in 7days,14days and less than 37 weeks were 1892%, 37.83%,46.65％； respectively,which were significantly higher than those women with nagetive fFN 0％,0％,3.57％;The negative predictive values were 100.0%,100.0% and 96.50%;CL was measured in 98 cases,22 of which with CL＜26mm.and 18cases of which were delivered within＜37weeks,The rate of preterm birth in those women with CL＜26mm within 7days,14days and less than 37 weeks were 22.72％,40.91％,81.82％;The sensitivity,specificity,positive and negative predictive value of shorter CL and positive fFN for preterm birth were 7647％,81.70％,92.30％and 94.37％，respectively. Conclusion(1)fFN was valuable in predicting preterm birth in women with preterm labor.Cervical lengh is also an important means for predicting the preterm birth.(2)The fFN combined with Cervical length can improve the accuracy of premature forecasting.