It's almost one in the morning, and I am discussing vaginas WAY too seriously.
Interestingly, given H. ducreyi’s infective habits, the pH of the vagina usually mimics skin pH, ranging between 4 and 7 (Omer et al, 1985). However, vaginal pH changes according to the menstrual cycle. Wagner and Ottesen (1982) observed that the mean vaginal pH in a study group fluctuated between 6.6 ±0.3 and 4.2±0.2, with acidity increasing as menstruation approached. Even vaginal secretions with pHs as low as 3.5 are not considered unusual (Castle et al, 2002). Some women are obviously on the low or high side of the given means at all times, which may affect their personal susceptibility to H. ducreyi infection. Conversely, existing infections can affect vaginal pH, possibly making it more hospitable to further infection. Das and Allan (2004) observed a correlation between Chalmydia trachomatis or Neisseria gonorrhoeae infections, and unusually alkaline vaginal pHs.
Some medications also alter vaginal pH, possibly helping to eliminate targeted infections, or abetting new ones (citation needed). The efficacy of pH regulation against infection can be seen in the use of acidic gel to prevent recurrences of bacterial vaginosis (Wilson et al, 2005). However, semen has a neutralizing effect on vaginal pH, which must be taken into account when considering heterosexual STD transmission (Tuyama et al, 2006).
Anyone know any good studies of drugs pharmaceuticals and vaginal pH?
ETA: GRRRR! Das and Allan established correlation, but causation, if anything, was shown to be in the other direction! NO! Now I need more research...