Identification of spontaneous preterm birth in symptomatic women by using cervicovaginal fluid biomarker and cervical length

To evaluate the performance of cervicovaginal fluid (CVF) fetal fibronectin (fFN) and cervical length (CL) at admission for predicting spontaneous preterm birth (sPTB) in women with symptoms of preterm labour. A cross-sectional study of 225 women with singleton pregnancy admitted to Prince of Wales Hospital, Hong Kong (n = 181) and Ramathibodi Hospital, Thailand (n = 44) at 24-36 weeks presenting with symptoms of preterm labour. Logistic regression analysis was performed to determine the significant predictors of sPTB. Area under the curves (AUCs) in different models were compared using DeLong test. There were 31 (13.8%) cases of sPTB with delivery <37 weeks. The average gestational age at admission was 212 (SD = 26.6) days. Women with sPTB had shorter admission-to-delivery interval than women with term delivery (p = <0.001). Analysis using multivariate logistic regression showed that CL (p < 0.001) and fFN (p = 0.001) made significant independent contributions to the prediction of sPTB. The AUCs for sPTB using CL or fFN alone were 0.748 (95%CI, 0.640-0.856) and 0.783 (95%CI, 0.689-0.876), respectively. The addition of fFN to CL, which is the baseline test in our clinical setting, significantly increased the predictive performance for sPTB with an AUC of 0.846 (95%CI, 0.774-0.917) compared to using fFN or CL alone (p < 0.05). For clinical consideration, utilising the cut-off values of CL<22.8 mm and fFN >258 ng/mL can identify 71% of sPTB cases with a false-positive rate of 18.6% (table 1). The combination of CL and fFN can provide effective prediction for sPTB among symptomatic women. These tools can aid triage and subsequent management of women presenting with symptoms of preterm labour. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.