What is pH?

pH is a scale that indicates the acidity and alkalinity. The range goes from 0 to 14, with 0 being the most acidic and 14 being the most alkaline. Water has a  pH of 7, which is generally referred to as pH neutral. A healthy vaginal pH value is somewhere between 3.8 and 4.5, well into the acidic range. The cause for this are the good bacteria living in the vagina that produce lactic acid that reduce the pH value.

The Importance of Vaginal pH

The acidic environment of the vagina is a natural barrier to infection and irritation, since it represses the growth of bad bacteria which prefer a less acidic environment. This means that as long as our good bacteria count is high and the vaginal pH is acidic, bad bacteria have a very slim chance of overgrowing, making the chance of infection low. As soon as the vaginal pH is increased above the value of 4.5, bad bacteria take the opportunity to develop and grow, eventually causing an infection. This can result in symptoms such as discharge, odor, itching and other vaginal discomforts. Changes in pH value are often connected to bacterial vaginosis.

What Causes Changes in pH?

pH value can change due to numerous factors.

  • Intercourse:  The alkaline pH value of semen is usually around 7.1-8. This can disturb the acidic environment of the vagina and stimulate BV-causing bacteria.
  • Menstruation:  Blood has a pH of 7.4, so during your period, vaginal pH becomes elevated
  • Menopause:  Can cause a reduction in estrogen levels which can reduce the numbers of lactobacilli, and eventually cause an increase in vaginal pH (thus, reduction in acidity).
  • Douching and cleansers: Anytime water or other liquids are put into the vagina, it can affect your vaginal pH.
  • Antibiotics:  These medications kill not only the good bacteria, but also the good ones that are responsible for keeping your vagina acidic and healthy.