Vaginal pH: definition and meaning
Vaginal pH is a measure of how acidic or alkaline the vagina is. A healthy vagina is moderately acidic, usually between 3.8 and 4.5 during the reproductive years, thanks to lactobacilli bacteria that make lactic acid. This acidity helps keep harmful bacteria and yeast in check. Menstrual blood, semen and menopause can temporarily raise the pH.
What changes vaginal pH
| Factor | Effect on pH |
|---|---|
| Period blood | raises it slightly (blood is around 7.4) |
| Semen | raises it for a few hours |
| Douching, scented washes | disturbs the balance; not recommended |
| Antibiotics | can reduce lactobacilli, making thrush more likely |
| Menopause | lower estrogen means fewer lactobacilli and a higher pH |
When pH points to an infection
A pH above 4.5 is common with bacterial vaginosis (BV), which causes a thin grey or white discharge with a fishy smell, often stronger after sex or a period. Trichomoniasis also raises pH. Thrush (yeast) usually keeps a normal pH but causes itching and thick white discharge. Learn what is typical in vaginal discharge and discharge types.
See a doctor or sexual health clinic if you have a strong or fishy smell, itching, soreness, a change in discharge color, or pain when peeing. Home pH tests can hint at a problem but can't tell which infection you have.
Keeping the balance
- Wash the vulva with plain water or a mild unscented wash; the vagina cleans itself.
- Skip douches and vaginal deodorants.
- Change pads, tampons and period underwear regularly.
- Some people find BV returns around their period; tracking can show the pattern to share with a doctor.
See also vulva and why period blood smells.
Frequently asked questions
Does vaginal pH change during the menstrual cycle?
Yes, it tends to rise slightly during the period because blood is less acidic, then settle again afterward.
Can diet change vaginal pH?
There is little good evidence that specific foods change it. Probiotics are being studied, with mixed results so far.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Vaginal discharge: definition and meaningVaginal discharge is fluid that keeps the vagina clean and healthy. What normal discharge looks like through your cycle and which changes need a doctor.
Discharge color chart: what each type means through your cycleA kind, clear discharge color chart: clear, white, creamy, egg white, yellow, green, gray, pink and brown discharge, what's normal and when to get checked.Vulva: definition and meaningThe vulva is the outside part of the female genitals: labia, clitoris and the openings of the urethra and vagina. Its parts, normal variation and care.
Why does period blood smell?Why does period blood smell? A light metallic smell is normal. What different period smells mean, how to stay fresh, and when an odor needs a doctor.Cervical mucus: definition and meaningCervical mucus is fluid made by the cervix that changes through your cycle. What each texture means, how it signals ovulation, and what's normal.