Preterm Birth Prediction by Measurement of Biomarkers in Cervical Vaginal Fluid

Preterm births (PTBs) refers to a delivery with a gestational age prior to 37 weeks, which can be divided into extreme PTBs (<28 weeks), early PTBs (28-32 weeks), and advanced PTBs (32-37 weeks). The prevalence of PTBs is on a global scale, with more than 1 million PTB per year in China (with a prevalence of 7%), ranking the second in the world. PTBs is the main cause of perinatal death. Meanwhile, premature infants are at higher risk of short-term or long-term complications such as respiratory distress syndrome and mental retardation, causing huge economic and mental burdens on families and society. Most PTBs are spontaneous or caused by premature rupture of membranes (PROM) while the precisely reason remains unknown. Effective early prediction of PTBs and timely intervention are key to reducing PTBs and improving adverse pregnancy outcomes. Current prediction methods for PTBs can be divided into the following three categories: risk factor assessment, cervical length measurement, and biomarkers. However, about half of premature pregnant women do not have high-risk factors, and only premature risk factors cannot accurately identify prematurely at-risk populations. Biomarkers such as fetal fibronectin (fFN) have a very high negative predictive value (more than 95%), but positive predictive value is low (with 200 ng/ml as a cut-off value, and fFN predicts a positive predictive value for preterm birth at <34 weeks gestation reaching only 37.7%). Other biomarkers such as hyperphosphorylated insulin-like growth factor binding protein-1 (phIGFBP1) and placenta α1 microglobulin (PAMG-1) were detected, but their predictive effects were still dissatisfactory.

Therefore, there is no currently effective screening method for predicting the occurrence of PTBs. How to accurately predict and diagnose PTBs is still an unsolved problem in obstetrics. Our previous study identified seven biomarkers in cervical vaginal fluid(CVF) that may be associated with preterm birth and preliminary validation in animal experiments, suggesting that biomarkers in selected CVF may be effective predictors of PTBs, but larger samples of clinical trials are required for validation.