The normal pH of the vagina is 4.5 or less, which is on the low, or acidic, side of the pH spectrum. This low pH helps to maintain a healthy balance of the yeast and bacteria that normally live in the vagina. If vaginal pH is raised, the normal balance of organisms can be upset, resulting in an inflammation known as vaginitis. Symptoms of a high vaginal pH causing vaginitis include irritation, unusual discharge or odor. A physician can test for vaginal pH using a pH test strip, or you can use a home vaginal pH test. Following certain hygiene and sexual practice guidelines can help to maintain a healthy vaginal pH.
Clean the vulva with plain, warm water. If you use soap, choose a mild soap, like perfume-free glycerin soap.
Change tampons and sanitary napkins frequently during menstruation. The pH of blood is 7.4, which is much higher than the pH of the vagina. Exposing the vagina to prolonged use of tampons and pads can lead to vaginitis.
Use a condom during sexual intercourse. With a pH of 7.1 to 8, semen is much more alkaline, or basic, than the vagina. Because of this, semen can alter the normal vaginal pH.
Refrain from douching. This can disrupt the normal vaginal pH and lead to vaginitis.
Some studies suggest that eating yogurt containing the probiotic bacteria Lactobacillus acidophilus can help prevent vaginal infections, perhaps through balancing pH. While clinical evidence for this is mixed, your doctor may recommend eating L. acidophilus, either in yogurt or in a tablet, as a preventive measure.
While an abnormally high vaginal pH is often a sign of vaginitis, it can also indicate the presence of sexually transmitted diseases, estrogen deficiency in menopause or pregnancy. Consult your healthcare provider if you believe you have an abnormal vaginal pH, or have any symptoms of vaginitis, including burning, itching or unusual discharge or odor. A negative result on a pH test can still indicate the presence of a yeast infection or other cause for irritation, so it is best to let your physician interpret the results.