pH can be measured on a scale from 0 to 14. A pH of 7 is considered to be neutral. A pH less than 7 is acidic while a pH greater than 7 is alkaline. The normal pH of a woman’s vagina is acidic and ranges between 3.8 and 4.5.Certain infections can increase the vaginal pH higher than 4.5.Menstruation also causes an increase in vaginal pH.

PH refers to the vagina’s acidity level. A vaginal pH of 3.5 - 4.5 indicates that there is a perfect amount of good bacteria (lactobacilli), and no overgrowth of the bad bacteria that can cause odour, irritation and sometimes infection

Healthy micro-organisms of the vagina

There are several micro-organisms that inhabit a healthy vagina. These micro-organisms are important as they help to keep the vagina healthy and protect against infection by disease causing bacteria, yeast, or other organisms that can enter the vagina. The most common type of beneficial vaginal bacteria in healthy women are called lactobacilli. This healthy type of bacteria secretes acids, which helps to maintain the acidic pH of the vagina (below 4.5).Disease causing organisms are less likely to survive in acidic conditions maintained by lactobacilli. There are several factors that can disrupt the healthy balance of micro-organisms and potentially lead to infections. These include the use of antibiotics, douching (washing out the vagina), hormone levels, sexual practices and a woman’s immune system.


Vaginitis is inflammation of the vagina, which may also involve the area around the vagina (vulva). It is often caused by infection, but other causes include a reaction to products such as soap, bath oils, spermicidal jelly and douches. Common symptoms of vaginitis are vaginal itching, discomfort and discharge.

Common infections that can cause vaginitis

Yeast infection

This common type of infection is caused by a type of yeast called Candida albicans. This infection is also called ‘thrush’ or candidiasis.

Common symptoms include itching and a white, lumpy discharge that looks like cottage cheese. Sometimes a woman experiences pain during intercourse.

These occur when there’s an overgrowth of a fungal organism – usually C. albicans – in the vagina. C. albicans also causes infections in other moist areas of the body, such as in your mouth (thrush), skin folds and nail beds. The fungus can also cause diaper rash.

Factors that increase risk of developing vaginitis include:

  • Hormonal changes, such as those associated with pregnancy, birth control pills or menopause
  • Sexual activity
  • Having a sexually transmitted infection
  • Medications, such as antibiotics and steroids
  • Use of spermicides for birth control
  • Uncontrolled diabetes
  • Use of hygiene products such as bubble bath, vaginal spray or vaginal deodorant
  • Douching
  • Wearing damp or tightfitting clothing
  • Using an intrauterine device (IUD) for birth control.


This is the most common vaginal infection in premenopausal women. 5 BV is associated with a loss or reduction of lactobacilli, overgrowth of other bacteria and elevated vaginal pH (>4.5). Common signs and symptoms include a thin milky vaginal discharge and a strong fishy odour.

This most common cause of vaginitis results from a change of the normal bacteria found in your vagina, to overgrowth of one of several other organisms. Usually, bacteria normally found in the vagina (lactobacilli) are outnumbered by other bacteria (anaerobes) in your vagina. If anaerobic bacteria become too numerous, they upset the balance, causing bacterial vaginosis.

This type of vaginitis seems to be linked to sexual intercourse – especially if you have multiple sex partners or a new sex partner – but it also occurs in women who aren’t sexually active.

Bacterial vaginosis signs and symptoms may include:

  • Thin, gray, white or green vaginal discharge
  • Foul-smelling ‘fishy’ vaginal odor
  • Vaginal itching
  • Burning during urination.

Many women with bacterial vaginosis have no signs or symptoms.

Risk factors for bacterial vaginosis include:

  • Having multiple sex partners or a new sex partner. Doctors don’t fully understand the link between sexual activity and bacterial vaginosis, but the condition occurs more often in women who have multiple sex partners or a new sex partner. Bacterial vaginosis also occurs more frequently in women who have sex with women.
  • The practice of rinsing out your vagina with water or a cleansing agent (douching) upsets the natural balance of your vagina. This can lead to an overgrowth of anaerobic bacteria, and cause bacterial vaginosis. Since the vagina is self-cleaning, douching isn’t necessary.
  • Natural lack of lactobacilli bacteria. If your natural vaginal environment doesn’t produce enough of the good lactobacilli bacteria, you’re more likely to develop bacterial vaginosis.

Other causes of vaginitis include:

Trichomoniasis: This common sexually transmitted infection is caused by a microscopic, one-celled parasite called Trichomonas vaginalis. This organism spreads during sexual intercourse with someone who has the infection.

In men, the organism usually infects the urinary tract, but often it causes no symptoms. In women, trichomoniasis typically infects the vagina, and might cause symptoms. It also increases a women’s risk of getting other sexually transmitted infections.

Genitourinary syndrome of menopause (vaginal atrophy): Reduced estrogen levels after menopause or surgical removal of your ovaries can cause the vaginal lining to thin, sometimes resulting in vaginal irritation, burning and dryness.


At its extreme, the result of too much bad bacteria is BV. BV, not yeast, is the most common cause of abnormal vaginal discharge, accounting for 40%-50% of cases.