The vaginal pH and leucocyte/epithelial cell ratio vary during normal menstrual cycles.

A higher proportion white blood cells (WBC) than vaginal epithelial cells in wet smears has been accepted as a sign which, together with clinical signs, can be useful in the diagnosis of infections in the genital tract such as cervicitis or salpingitis. However, little is known about the normal variation among healthy women without any symptoms or signs of genital-tract infection. By taking frequent wet smears from three healthy asymptomatic women during four menstrual cycles we found that vaginal leucocytosis usually occurred once each cycle. Normal vaginal leucocytosis must thus be taken into consideration when evaluating wet smear of patients for genital tract infections.