Human Chorionic Gonadotropin in Cervicovaginal Secretions as a Predictor of Preterm Birth

Objective: To compare the qualitative (QL) and quantitative (QN) levels of βhCG in cervicovaginal secretions as predictors of preterm birth. Methods: The study included 100 women. QL and QN assays were done with velocit kit and ELISA, respectively. Results: A positive QL assay had sensitivity of 78%, specificity 95%, positive predictive value (PPV) 90%, negative predictive value (NPV) 88% and odds ratio (OR) = 70.87 (95% CI = 18.50, 271.50). The likelihood ratios (LRs) for positive and negative tests were 15.6 and 0.06, respectively. Using a cutoff value of 34.5 mIU/ml, the QN assay had sensitivity of 86%, specificity 86%, PPV 78% and NPV 92%, OR = 36.90 (95% CI = 10.79, 126.15). The LRs for positive and negative tests were 6.14 and 0.16, respectively. Conclusion: The simple and cheaper QL βhCG test is a better predictor of preterm birth as compared to the QN test. Copyright © 2009 S. Karger AG, Basel.