Quantitative and Qualitative Measurement of Vaginal Fluid β-HCG for the Diagnosis of Premature Rupture of Membranes

Premature rupture of membranes (PROM) is known as one of the leading causes of morbidity and mortality among pregnant women. So, the aim of this study was to evaluate the diagnostic value of quantitative and qualitative vaginal fluid β-HCG for the detection of premature rupture of membranes.
One hundred pregnant women with gestation age between 28 and 37 weeks were divided into three groups: confirmed PROM group (34 cases), suspected of PROM (36 cases), and intact membranes (30 cases). Those pregnant women with positive pooling tests were considered as confirmed PROM, while those with the decreased amniotic fluid index, positive nitrazine, or ferning were included in suspected PROM group. Notably, pregnant women with no complaints or complications were enrolled as the control group. Five ml sterile normal saline was injected into the posterior fornix of vagina, vaginal fluid was aspirated, and β-HCG measurement was then performed both quantitatively and qualitatively using ELISA and baby check kits, respectively.
The cut-off value for quantitative β-HCG was determined as 66 mIU/m. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of quantitative β-HCG were calculated as 97.05%, 100%, 100%, 96.77%, and 98.43%, respectively. Besides, the qualitative vaginal washing fluid β-HCG using Baby check with the threshold value of 25 mIU/ml had 94.11% sensitivity, 93.33% specificity, 94.11% PPV, 93.33% NPV, and 93.75% accuracy.
Quantitative and qualitative vaginal washing fluid β-HCG measurements are accurate, reliable, and useful tests for the diagnosis of PROM.