Preterm Birth Prediction With Fetal Fibronectin and Cervical Length in Pregnant Women With Preterm Labor

Objective To investigate the predictive value of fetal fibronectin(fFN) and cervical length alone and combination for preterm birth in pregnant women with preterm labor. Methods fFN level in discharges from the posterior fornix and cervical length under vaginal ultrasound scan were measured for the subjects who presented with preterm labor between 22~35 gestational weeks with intact membranes, cervical dilation <3 cm and without previous tocolysis. All subjects outcomes were recorded and the sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of fFN, cervical length and their combination were analyzed statistically. Results ①Among 176 cases, positive fFN was detected in 24 cases. The prevalence of spontaneous preterm delivery among those women with fFN(+ ) within 7 days, 14 days and less than 37 weeks were 20.8%, 29.2%, 33.3%. No preterm birth occurred among those 152 women with fFN(-). ② In 124 pregnant women with preterm labor, 9 cases' cervical length was less than 2.6 cm, and 6 cases of which were delivered within 14 days. No preterm birth occurred among the 115 cases with cervical length longer than 2.6 cm. ③The sensitivity, specificity, PPV and NPV of fFN for preterm birth were 100%, 90.5%, 33.3% and 100%, and for cervical length, they were 100%, 97.5% 66.7% and 100%. For their combination the sensitivity, specificity, PPV and NPV were 100%, respectively. Conclusion fFN is valuable in predicting preterm birth in women with preterm labor, especially significant for NPV. cervical length is also an important means for predicting the preterm birth, and fFN combined with cervical length can improve the PPV of preterm delivery less than 37 weeks. Key words: fibronectin; ultrasonography; cervical length; premature forecasting