You’re probably familiar with the importance of maintaining your gut health —where the body needs to maintain a delicate equilibrium between good and bad bacteria that are present in the intestines. Diet, nutrition, and medications all play a role in maintaining this balance of bacteria in the gut.1 But did you know that the vagina also has its own microbiome? This isn’t talked about nearly as often, but maintaining a similar balance, just like in the gut, is an important part of supporting your overall health.
When an imbalance occurs, symptoms such as vaginal discharge, itching, odor and irritation, (common symptoms of vaginitis or inflammation of the vagina) may start. This is not uncommon— with 75% of women having experienced vaginitis at least once in their lifetime—but it is something that may require medical attention to treat.2
The Vaginal Microbiome
An assortment of microbes live in the vagina, where it’s warm and moist—a perfect environment for them to thrive. In exchange for a cozy roosting place, these microbes provide antimicrobial and anti-inflammatory benefits. A healthy vaginal microbiome has an abundance of Lactobacilli bacteria (“good” bacteria) that produce various anti-microbial compounds, which are needed to stave off growth of "bad," inflammatory-causing bacteria. This vaginal microecosystem does change throughout a woman’s life due to hormonal fluctuations commonly experienced during reproductive years or the menopausal transition, but external factors can influence this balance, too.3
What is the pH of the Vagina?
A basic chemistry concept can be used to better understand the vaginal microbiome: the pH scale. The vagina's balance is measured using pH values, which determine how acidic or basic (aka alkaline) a substance or environment is. The pH scale ranges from 0-14, where a pH of 7 is neutral, less than 7 is acidic, and higher than 7 is basic (alkaline). The vagina, in general, tends to favor an acidic pH, which is helpful for eliminating bad bacteria and preventing infections.4
Do All Women Have the Same Vaginal pH Levels?
Because our bodies are all slightly different, healthy, normal vaginal pH levels may vary from one woman to the next. A normal vaginal pH falls between 3.8-4.5 (moderately acidic), with a typical value being less than 4.5. However, even within a single body, vaginal pH levels aren’t necessarily always the same. Vaginal pH is influenced by various factors, like how hydrated the vagina is, what you eat on a daily basis, and whether or not you’ve engaged in unprotected sex. Vaginal pH values also correlate to age. Normal vaginal pH levels for women during their reproductive years are typically between 4.0-4.5, and they can increase to over 4.5 in perimenopausal and postmenopausal women.5
What Causes Vaginal pH to Change?
A number of factors can influence pH levels in the vagina. Some can be controlled, while others occur no matter what steps a woman may take to prevent an imbalance. Several things that can cause vaginal pH to change include:
During a woman's reproductive years, a healthy vaginal pH is about 4.5 or less. But before menstruation begins and after menopause, these levels tend to be higher. As women approach menopause, it's a good idea to be on alert for any noticeable vaginal changes that may hint at a possible infection.6
Bacterial vaginosis (BV) occurs when excess “bad” bacteria is present in the vagina, which may upset the natural bacterial balance and raise vaginal pH levels.7 Other infections such as Trichomonas vaginalis and Group B Streptococcus (GBS) may also increase vaginal pH levels.8
Taking antibiotics for infections located elsewhere in the body sometimes eliminates good bacteria in the vagina. Some medications also increase vaginal pH levels, which may result in a secondary infection due to an abundance of harmful bacteria. Penicillin-based drugs, such as amoxicillin, are one type of antibiotic that may throw off balance in the vaginal microbiome, causing an infection.9
Semen is considered to be an alkaline substance; therefore, it’s known to increase vaginal pH levels. Even if you’re engaging in sexual activity with the same partner, semen does have the potential to raise vaginal pH levels. To prevent exposure to ejaculate, consider using condoms; they not only protect against unwanted pregnancy; but they also create a barrier for sexually transmitted diseases, which can negatively affect vaginal pH as well.10
Lubricants help reduce vaginal dryness during sex. It’s important to note that some products have a pH higher than 4.5, which can kill healthy bacteria and lead to an infection.11 Consider avoiding petrolatum-based lubricants as they have a higher likelihood of changing your vaginal pH as compared to water or silicone-based products.12
The vagina is a self-cleaning organ and douching with vinegar or soaps may disrupt the delicate balance of bacteria. Most healthcare professionals recommend against douching; instead, consider using plain, warm water with or without a gentle cleanser to clean the vulva, but refrain washing inside the vagina to maintain pH levels. 13
What’s Considered to Be a Normal Vaginal pH?
We’ve already mentioned that vaginal pH levels may be age dependent. Here’s why: normal vaginal pH values for reproductive-aged women typically fall between 4.0-4.5, but in premenopausal and postmenopausal women, it’s not uncommon for levels to increase to 4.5 or slightly higher.14 Lower estrogen levels, which are a hallmark symptom of menopause, also affects vaginal pH.15
How Do I Know If My Vaginal pH Levels are Off?
There may be times you just feel something isn’t right with your body, but you can’t quite determine what’s going on. Fortunately, over-the-counter pH testing kits are available for women who want to check their vaginal pH levels. These kits are equipped with special paper test strips that are designed to be inserted in the vagina. They also include a color chart, and once the testing strip turns a specific color, it can be compared with the color on the chart to determine what the pH level is.16 If you’ve tried an at-home vaginal pH test and determined your levels are off, it’s best to check-in with your healthcare provider to better understand what could be causing the imbalance, and to rule out any underlying causes or infections.
Some telltale symptoms are hard to ignore, and may tip you off to a potential vaginal pH imbalance or infection, including: 17
- A foul or fishy odor
- Unusual white, gray, green, or foamy discharge
- Vaginal itching
- Burning when urinating
You should always seek treatment from your healthcare provider if you experience any of these issues or if you’re concerned you may be struggling with a vaginal pH imbalance.
The vagina is a complex organ with a unique—but scientifically interesting—microbiome. Understanding some basic facts about how pH levels affect vaginal health can help women take steps to stay healthy, and potentially avoid future infections.