RESUMEN
OBJECTIVE: To evaluate the reliability of vaginal washing fluid beta-HCG for the diagnosis of premature rupture of membranes (PROMs) and to determine a cut-off value. STUDY DESIGN: A total of 141 pregnant women were recruited. The first group consisted of 73 pregnant women between 14 and 41 weeks of gestation with the complaint of vaginal fluid leakage. These were further subdivided into two subgroups. Group 1-confirmed PROM group (amniotic fluid pooling (+) and nitrazine paper test (+); 34 patients). Group 2-suspected but unconfirmed PROM group (amniotic fluid pooling (+/-) and/or nitrazine paper test (+/-); 39 patients). The control group (Group 3) consisted of 68 pregnant women between 14 and 41 weeks of gestation without any complaint or complication. All patients underwent speculum examination for amniotic fluid pooling, nitrazine paper test, vaginal washing fluid beta-HCG sampling and ultrasonographic examination for gestational age determination, amniotic fluid index calculation. One-way ANOVA test, Scheffe multiple comparison test and receiver operating characteristic (ROC) curve analysis were used. RESULTS: Geometric mean values of beta-HCG was found to be 95 for Group 1, 14 for Group 2, 10 for Group 3 (P<0.0001). The optimal cut-off was a beta-HCG value of 65 mIU/ml (sensitivity 68%, specificity 95%, positive predictive value 82%, negative predictive value 90%, accuracy 87%). CONCLUSION: Vaginal washing fluid beta-HCG determination for the diagnosis of PROM is reliable, simple and rapid test.