What is Bacterial Vaginosis

What is Bacterial Vaginosis


Bacterial vaginosis or BV is caused by when the balance of bacteria in the vagina becomes disrupted, resulting in an increased ph level when the allows other types of bacteria to grow.

Bacterial Vaginosis doesn't usually cause any vaginal soreness or itching but often causes unusual vaginal discharge and odour.
The symptoms are characterised by:
Fish-like odour, white or grey discharge which can become thin and watery

BV isn't serious for the vast majority of women, although it may be a concern if symptoms of BV develop in pregnancy and you have a history of pregnancy-related complications.
50% of women with bacterial vaginosis have no symptoms.

Causes of bacterial vaginosis

Bacterial vaginosis (BV) occurs when there's a change in the natural balance of bacteria in your vagina.
Your vagina should contain bacteria called lactobacilli, which produce lactic acid.  This makes the vagina slightly acidic, which prevents other bacteria from growing there.
Women with BV tend to have a temporary shortage of lactobacilli, which means their vagina isn't as acidic as it should be.  This allows other types of bacteria to grow.

It's still unclear what causes this change, although your risk is increased if you:

  • are sexually active, particularly if you have a new sexual partner or multiple sexual partners
  • use an intrauterine device (IUD) - a contraceptive device that fits inside the womb
  • smoke

For reasons that are unclear, BV is more common in black women than in other ethnic groups.

Is Bacterial Vaginosis a Sexually Transmitted Infection?

BV isn't generally considered a sexually transmitted infection (STI).  However, there's conflicting evidence on the subject.
Evidence that suggests BV may be an STI includes:

  • rates of BV are higher in women who have multiple sexual partners
  • rates of BV are lower in women who use a condom during sex

There's also evidence that women with BV can pass the condition to women they have sex with, although how this happens is still unclear.
However, there's also evidence to suggest BV may not be an STI, as:

  • there's no equivalent of BV in men
  • treating male partners with antibiotics doesn't prevent the recurrence of BV
  • rates of BV can vary significantly in different ethnic groups, which can't be explained by sexual activity alone

BV can sometimes occur in women who aren't sexually active
Many experts think sexual activity plays a role in BV, but other factors are probably also responsible for the condition.

Treating bacterial vaginosis

Bacterial vaginosis (BV) can be treated successfully with antibiotics.
There's currently no evidence that probiotics, such as those found in some yoghurts, are able to treat or prevent BV.


Metronidazole is the most common and preferred antibiotic treatment for BV.  It's available in three forms.  These are:
Metronidazole 500mg tablets or Metronidazole 400mg tablets to be taken twice a day for five to seven days
Four tablets of Metronidazole 500mg as single dose, you take only once
Zidoval, a gel you apply to your vagina once a day for five days
In most cases, metronidazole tablets taken over five to seven days are recommended, as they're considered to be the most effective treatment.  These can be taken if you have symptoms of BV while you're pregnant.
If you're breastfeeding, metronidazole gel is usually recommended, as the tablets can affect your breast milk.
Occasionally, an alternative antibiotic may be recommended instead of metronidazole, such as clindamycin cream, Dalacin Vaginal Cream, applied to the inside of the vagina once a day for seven days.  This cream may be prescribed if you've had a reaction to metronidazole in the past, for example.
Whichever course of antibiotics you're prescribed, it's important to finish it, even if you start to feel better.  This helps to reduce the risk of symptoms persisting or recurring.

Vaginal pH correction treatments

Vaginal pH correction treatments are a relatively new way of treating BV.  These usually involve applying a gel to the inside of your vagina that changes the acid balance, making it a less hospitable environment for harmful bacteria.  Most vaginal pH correction treatments are available over the counter from pharmacists.
Balance Activ