The value of measurement of vaginal fluid creatinine and beta-human chorionic gonadotropin in the diagnosis of premature rupture of membranes

INTRODUCTION: The purpose of the present study is to evaluate β-human chorionic gonadotropin (β-hCG) and creatinine levels in the vaginal fluid regarding to diagnosis of premature rupture of membranes (PROM).
METHODS: This study was conducted on 150 pregnant women in the third trimester (28–40 weeks). The patients were grouped as: (1) PPROM group (75 cases) and (2) intact membranes as control group (75 cases). Three milliliters of sterile normal saline were inserted into the posterior fornix of the vagina and then vaginal fluid was aspirated. Creatinine and β-hCG levels in the vaginal fluid were measured β-hCG and creatinine levels were compared between the two groups.
RESULTS: The mean vaginal fluid level in Groups 1 and 2 was 0.60±0.72 (0.37) and 0.22±0.11 (0.2) for creatinine and β-hCG which was positive in 411.69±605.65 (146) and 12.71±24.63 (3.9), respectively. There was a statistically significant difference regarding to mean creatinine and β-hCG levels between two groups (p<0.001). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were all 66.67%, 96%, 94.3%, 74.3%, and 81.3% for creatinine and 94.6%, 82.6%, 84.52%, 93.94%, and 88.67% for β-hCG in detecting PROM with a cutoff value of 0.21 mg/dl for creatinine and 16 mIU/ml for β-hCG.
DISCUSSION AND CONCLUSION: Measuring of β-hCG level in vaginal fluid is accurate, cheap, and simple methods in the diagnosis of PROM. Furthermore, measuring of creatinine level is a simple and accurate method with a lower sensitivity and accuracy than for β-hCG.