pH is a measurement of how acidic or alkaline (basic) a substance is. The scale runs from 0 to 14. A pH of less than 7 is considered acidic, and a pH of more than 7 is basic.
What does any of this have to do with your vagina?
The pH level of your vagina — whether it’s acidic or basic — plays an important part in determining whether it’s healthy.
Keep reading to learn more about healthy pH levels, how to correct an imbalance, and how to maintain overall vaginal health.
A normal vaginal pH level is between 3.8 and 4.5, which is moderately acidic. However, what constitutes a “normal” pH level can vary slightly based on your stage of life.
For example, during your reproductive years (ages 15 to 49), your vaginal pH should be below or equal to 4.5. But before menstruation and after menopause, a healthy pH tends to be higher than 4.5.
So why does vaginal pH matter? An acidic vaginal environment is protective. It creates a barrier that prevents unhealthy bacteria and yeast from multiplying too quickly and causing infection.
A high vaginal pH level — above 4.5 — provides the perfect environment for unhealthy bacteria to grow. Having a high vaginal pH puts you at risk for these infections:
Bacterial vaginosis (BV) is a bacterial overgrowth condition that causes a “fishy” odor, along with an unusual gray, white, or yellow vaginal discharge. It can also result in vaginal itchiness and burning during urination. BV isn’t necessarily harmful in itself, but women who have this condition are at increased risk for more serious infections like human papillomavirus (HPV), herpes simplex virus, and HIV.
Trichomoniasis (trich) is a sexually transmitted disease (STD) caused by the parasite Trichomonas vaginalis. In the United States, it affects an estimated 3.7 million people. Trich usually doesn’t cause symptoms in the majority of those infected, but it can increase your risk for other, more serious STDs, like HIV.
An acidic vagina usually doesn’t cause disease. But if the acidity rises too much, it might reduce your fertility. Sperm thrive in an alkaline environment. The optimal pH for them to swim is between 7.0 and 8.5. During sex, the pH level inside the vagina temporarily rises, making the normally acidic environment more alkaline to protect the sperm so they can make their way to the egg.
Any of the following situations can change your vaginal pH level:
- Unprotected sex. Semen is alkaline, which can encourage growth of certain bacteria.
- Antibiotics. These drugs kill not only the bad bacteria that cause disease, but also the good bacteria you need to maintain a healthy, more acidic, vaginal pH level.
- Douching. Although it isn’t advised, about 20 percent of women regularly wash out their vagina with a mixture of water and vinegar, baking soda, or iodine. Douching not only increases the vaginal pH level, but also encourages the growth of harmful bacterial overall.
- Menstrual periods. Menstrual blood is a little bit basic and raises the pH in the vagina. When that blood flows through the vagina and is absorbed into a tampon or pad and sits in place, it can raise the pH level of the vagina.
A high pH level that leads to BV or another infection may cause symptoms like these:
- a foul or fishy smell
- unusual white, gray, or green discharge
- vaginal itching
- burning when you urinate
If you have symptoms of BV or another condition that’s linked to a high vaginal pH, see your doctor. Don’t try to douche — it will only throw off your pH balance even more.
To treat a BV or trichomoniasis infection, your doctor might prescribe one of these antibiotics by pill or cream:
- clindamycin (Cleocin) for BV
- metronidazole (Flagyl) for BV or trichomoniasis
- tinidazole (Tindamax) for BV or trichomoniasis
To keep the pH of your vagina at a consistently healthy level, follow these tips:
1. Whenever you have sex, use a condom. The barrier will not only protect you from STDs, but it will also prevent alkaline semen from disrupting your vaginal pH levels.
2. Take probiotics to restore the balance of healthy bacteria to your system.
3. Don’t douche. It can increase the pH level in your vagina. Your vagina is naturally self-cleaning. Wash only the outside of your vagina with a mild soap and water when you shower. If you’re concerned about odor, ask your OB-GYN for advice.
4. Eat yogurt. In addition to helping you reach your daily quota of calcium and vitamin D, yogurt is a plentiful source of the beneficial bacterial species of Lactobacillus.
5. See your OB-GYN for regular exams to help maintain your vaginal health.
Visit your OB-GYN for regular checkups to ensure that your vagina stays healthy.
See your doctor between scheduled visits if you have these symptoms:
- foul odor
- unusual discharge
Your doctor can do tests to check the pH level of your vagina, among others, and diagnose an infection if you have one.