Antenatal vaginal pH screening for vaginitis

Abstract

This research studied in pregnant women who came to prenatal care clinic of Srinagarind Hospital, Faculty of Medicine, Khon Kaen University for the first visit. The objectives of the study were to assess the diagnostic performance of vaginal fluid pH to screen for vaginitis and the prevalence of vaginitis in pregnant women. During November 1994 to February 1995, the pregnant women who came to the hospital for first visit of antenatal care were recruited into the study after personal informed and asked for permission. If there/ were any suspicious of pregnancy complication or vaginal examination would be harmful for them, they would not be recruited into the study. The prevalence of vaginitis in pregnant women, which was documented by the gold standard tests, at the first visit of antenatal care at Srinagarind hospital was 31.3% (80/256. From a total of 80 cases, the vaginal fluid pH can correctly detect 51 cases resulting in a sensitivity of 63.8%. From a total of 176 women who were not classified as having vaginitis by the gold standard tests, the vaginal fluid pH can classify as so in 159 cases resulting in a specificity of 90.3%. The positive predictive value and the negative predictive value are 75.0% and 84.6% respectively. The vaginal fluid pH test has higher- sensitivity in screening for bacterial vaginosis cases (Sensitivity = 100.0 % Specificity = 77.7%) than for non bacterial vaginosis cases (Sensitivity =51.4%, Specificity = 77.3%). Since the prevalence of non bacterial vaginosis in the study setting IS 2.6 times greater than that of bacterial vaginosis (14.1%/5.5), the sensitivity of the test being studied IS, therefore, unsurprisingly low. However, the test can detect 61.7% (37/60) of asymptomatic vaginitis cases or 46.3% (37/80) of the total vaginitis cases. Vaginal pH combined with clinical symptoms and signs can detect 71.3% (57/80) of the total vaginitis cases. The vaginal fluid pH test has low sensitivity in screening for vaginitis, in the situation that the proportion of non bacterial vaginosis is relatively higher than that of bacterial vaginosis. Therefore, vaginal fluid pH test alone may not appropriate to be used as a screening test for vaginitis in such circumstance. However clinical symptoms and signs combined with the vaginal fluid pH test is found to be quite sensitive in detecting vaginitis during pregnancy.