Vaginal discharge concentrations of β-human chorionic gonadotropin, creatinine, and urea for the diagnosis of premature rupture of membranes.

Abstract

To determine the diagnostic value of vaginal discharge concentrations of β human chorionic gonadotropin (β-hCG), creatinine, and urea to identify premature rupture of membranes (PROM). An observational cross-sectional study was conducted between 12 June, 2014, and 11 June, 2015, among 120 women who were admitted to an Iranian hospital at 28-41weeks of pregnancy. Women with positive pooling and nitrazine test results were assigned to the PROM group (n=60), whereas those with negative test results were assigned to the control group (n=60). Samples of vaginal discharge were obtained. Mean concentrations of β-hCG, urea, and creatinine were all higher in the PROM group than in the control group (all P=0.001). The diagnostic accuracies as defined by area under the curve for creatinine, urea, and β-hCG were 0.891, 0.895, and 0.908, respectively. The corresponding optimal cutoff values were 20.33μmol/L, 0.94mmol/L, and 39.5IU/L, respectively. The vaginal discharge concentrations of all three markers exhibited favorable predictive value for the diagnosis of PROM; however, β-hCG showed greater diagnostic accuracy than either urea or creatinine.