Bacterial vaginosis: prevalence and value of different diagnostic tests among prenatal women at Kenyatta National Hospital
Bacterial Vaginosis (BV) is defined as an imbalance in the normal vaginal flora with a reduced level of the usual predominant lactobacilli and the proliferation of various anaerobic bacteria. 79 BV is associated with amplified risk of pregnancy losses, maternal and neonatal morbidity and mortality. Between 25% and 60% of preterm births are thought to be attributable to maternal infections, and are thus considered preventable. BV is fairly common, with a prevalence ranging from 10% to 30% in a typical obstetrical population to more than 50% in some high-risk groups. OBJECTIVE: This was to determine the prevalence of BV and value of diagnostic tests for Bacterial Vaginosis in women attending Antenatal clinic at Kenyatta National Hospital. STUDY POPULATION AND AREA: A total of 190 women attending the Antenatal clinic at Kenyatta National Hospital between March and May 2011 were included in the study. MAIN OUTCOME MEASURES: These included Prevalence of Bacterial Vaginosis and the Validity of diagnostic tests for BV (KOH Amine test, Vaginal PH, and clue cells) against the Gram stain method (the Gold standard test for diagnosis of BV). DESIGN: This was a cross-sectional study METHODOLOGY: The selected clients all underwent a sterile pelvic exam and were evaluated for clinical and microscopic presence of BV. The prevalence of Bacterial Vaginosis was calculated from the results. The clinical diagnosis criteria were validated against the Gram stain which is the gold standard. DATA ANALYSIS: This was done using the Statistical Package for Social Scientists (SPSS) 17.0. Data was summarized and presented in tables, charts and graphs. Chi-square (l) test and odds ratio (OR) were used to describe data. RESULTS: Of the 190 study participants 26% were found to be positive for BV. Higher odds for BV were seeAin older women, unmarried with lower education level and also in participants with prior history of 5TI treatment, prior miscarriage and HIV positive, Clinical criteria had high specificity of more than 95% when validated against gram stain and a low sensitivity of less than 10%. Individually Vaginal PH had the highest sensitivity against Gram stain of more than 95% while the other variables (KOH AMINE test, and Greyish Vaginal Discharge) individually had very high specificity of more than 95%. RECOMMENDATIONS: High prevalence of BV in our population necessitates routine screening of High risk antenatal women. These include those with prior history of STI, prior miscarriage, or positive for HIV. Vagina PH has a very high sensitivity and can individually be used as a screening tool. Hence we should equip our antenatal clinics with PH strips which can be used for screening purposes for BV. For diagnosis either Gram stain or Amsel clinical criteria can be used as the clinical criteria was found to have almost similar specificity as the Gram stain method of more than 95%.