To evaluate the frequency of yeast, bacteria or protozoa in pregnant women and to correlate the possible associations of these microorganisms and their relationships with vulvovaginitis (VV) and cervicitis. Vaginal specimens were collected and prepared for smears in microscope slides for the evaluation of yeast, Trichomonas vaginalis and bacteria. Samples were cultured in specific culture medium. Cervical specimens were used to investigate the presence of Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma spp. and Mycoplasma hominis. We enrolled 210 pregnant women, aged 10-42 years old. Of them, 38.1% were symptomatic. Symptoms were most prevalent in the second and third trimesters of pregnancy coincident with a major prevalence of microorganisms. In this study, 39.5% of pregnant women had normal microbial biota and symptoms of VV due to non-infectious causes were observed (6.2%). The occurrence of vulvovaginal candidiasis was 25% and Candida albicans with a prevalence of 80.7% was the dominant species (P = 0.005) while non-albicans Candida species and other yeast were more common in asymptomatic ones (P = 0.0038). The frequency of bacterial vaginosis, T. vaginalis, C. trachomatis and N. gonorrhoeae were 18.1%, 1.4, 1.4% and 0.5% respectively.