In case you haven’t noticed, vaginas are complex. On the one hand, they’re self-cleaning and go through a lot during childbirth. On the other hand, we’re constantly reminded that they’re also a “delicate environment,” which requires a balanced pH. But that sounds more like a biology project than a body part. What are we really talking about when we mention “vaginal pH”? We’ve asked a few OB-GYNs to weigh in.
What is vaginal pH?
According to Dr. Mache Seibel, an OB-GYN, it’s helpful to think of the vagina in more familiar terms.
“Think of a swimming pool and how the pH has to be adjusted for optimum conditions,” he tells SheKnows. “When conditions are optimal, it prevents algae from growing in the pool. The vagina is an ecosystem with lots of bacteria naturally living there; pH is a measurement of the ‘acidity’ or ‘alkalinity’ of the vagina,” he says. “When the pH of the vagina is in ideal, the levels of ‘good’ and ‘bad’ bacteria are in balance and the vaginal ecosystem is healthy.”
Similarly, Dr. Lauren Streicher, an OB-GYN and medical director of the Northwestern Medicine Center for Sexual Medicine and Menopause and associate clinical professor of obstetrics and gynecology at Northwestern University, tells SheKnows that most people with vaginas don’t realize the vagina is an ecosystem that requires a balanced environment to remain healthy. Normal bodily functions — like menstruation, sex and hormonal changes — can throw off that balance, she says, adding that the result can be odor and discomfort.
“Many women never have the benefit of a frank, open discussion about vaginal health and the importance of maintaining a healthy pH balance ‘down there,’” Streicher explains. “Healthy pH and beneficial lactobacillus are the keys to reducing the risk of vaginal issues.”
What’s a "normal" vaginal pH?
The pH scale has a range of 1 to 14; 7 is neutral (and the pH of water), with anything less than 7 being acidic and anything greater than 7 being alkaline, Seibel notes.
Believe it or not, vaginas are naturally acidic, he says.
“Most people think of acid as bad (as in your esophagus),” Dr. Mary Jane Minkin, an OB-GYN and clinical professor of obstetrics and gynecology at Yale University, tells SheKnows. “However, in the vagina, acid is good, and a good pH in the vagina is, say, in the 4 to 4.5 range.”
So, what keeps the vagina acidic? According to Minkin, "good guy" bacteria known as lactobacilli make acid. “When the vagina gets dry, for example, with menopause — low estrogen states — the vaginal cells lose glycogen, which is a delicious substance for lactobacilli,” she explains. “Without glycogen, lactobacilli lose their major nutrient and die off.”
What throws off vaginal pH balance?
When the vagina is either too acidic or too alkaline, bacterial overgrowth can occur, which leads to vaginal discharge and/or discomfort, Seibel says.
But as Streicher notes, a range of normal vaginal events can trigger elevated pH levels on a regular basis. According to Streicher, these include:
Periods: The pH of blood is 7.4, which is much more alkaline than normal vaginal pH, which can lead to elevated vaginal pH.
Sex: Semen has a pH of 7.1 to 8 and can increase vaginal pH.
Hormones: Pregnancy, menopause and your normal monthly cycle can cause hormone changes that alter vaginal pH.
Seibel adds two more to the list:
Antibiotics: Taking antibiotics not only kill the bad bacteria, but also the good ones that keep the vagina more acidic.
Douching: Douching washes out the normal vaginal bacteria. For that reason, douching is no longer recommended.
How do you know if something is off down there? Seibel says that symptoms of a vagina without a normal pH include itching, burning, foul odor and unusual discharge.
If you want to test your vaginal pH at home, Seibel says that the best method is to purchase pH paper at the drugstore. When you get home, hold the paper against the wall of your vagina for a few seconds, and then compare the color of the paper with the color chart that is provided. There are also several commercially available pH test kits at drugstores, he adds.
If the test results indicate that your vaginal pH is way off or if you’re experiencing unusual symptoms, it’s a good idea to see your doctor to make sure you stay in balance.