Composition of vaginal microflora in relation to vaginal pH and wet mount diagnostic tests in the first trimester of pregnancy

The aim of the study was to determine the relations between vaginal culture results, elevated vaginal pH and abnormal vaginal microflora observed in microscopy, during the first trimester of pregnancy. A cross-sectional, observational study of 100 women receiving antenatal care in five outpatient clinics was carried out in Riga from March 2010 until April 2011. Pregnant women at the first antenatal visit were submitted to a vaginal specimen collection for pH measurement, wet mount and cultures. Fifty pregnant women with vaginal pH 4.5 and 50 subsequent pregnant women with vaginal pH less than 4.5 were included. 96% of women with increased pH and 86% of women with normal vaginal pH showed positive cultures. Increased vaginal pH was significantly associated with M. hominis (P < 0.001), U. urealyticum (P = 0.017) and E. coli (P = 0.018). Abnormal vaginal microflora patterns showed similar associations with culture findings. Multivariate logistic regression analysis showed the highest risk of abnormal vaginal microflora associated with M. hominis (OR 14.4, 95% CI 1.6-124.4, P = 0.015) and E. coli (OR 8.5, 95% CI 1.6-45.9, P = 0.013). Increased vaginal pH and abnormal vaginal microflora pattern in wet mounts was associated with M. hominis and E. coli in vaginal cultures.