Human chorionic gonadotropin in cervicovaginal secretions as a predictor of preterm delivery.

OBJECTIVES To determine whether human chorionic gonadotropin (hCG) detected in cervicovaginal secretions of patients with symptoms suggestive of preterm labor is a predictor of preterm birth. METHODS Women presenting to labor and delivery with symptoms of preterm labor were invited to participate. After collecting secretions with a cotton-tipped applicator from the posterior fornix and endocervical canal, we placed the swab in a test tube containing 1 ml of normal saline. From this solution, we performed qualitative and quantitative hCG measurements. Qualitative and quantitative hCG results from women who delivered at term were compared with those delivering prior to 37 weeks' gestation. RESULTS Samples were obtained and analyzed from 86 women at a mean (+/- standard deviation) gestational age of 30.7+/-2.9 weeks. Of the 86 subjects enrolled, 28 (32.6%) delivered preterm. A positive rapid qualitative assay from cervicovaginal secretions between 24 and 34 weeks' gestation was associated with a significant increase in the incidence of preterm delivery (relative risk 2.62, 95% confidence interval (CI) 1.38, 4.98). The likelihood ratios for a positive and negative test were 2.19 (95% CI 1.35, 3.56) and 0.51 (95% CI 0.30, 0.85) respectively. Using a cut-off of 19 mIU/ml, similar diagnostic accuracy for predicting preterm birth was obtained with the quantitative test 1.93 (95% CI 1.14, 3.26) and 0.62 (95% CI 0.40, 0.98). CONCLUSIONS Qualitative and quantitative hCG measurements from cervicovaginal secretions may be useful predictors of preterm birth in symptomatic patients. The qualitative hCG test can be used at the bedside with results obtained in minutes.