What causes Bacterial Vaginosis?

A woman’s vagina contains many different types of bacteria, collectively known as flora. Usually, they all live in harmony to help keep you and your vagina healthy.

But if the balance of bacteria is disrupted for any reason certain ones can overgrow, leading to bacterial vaginosis, or BV for short.

You can still have BV, even if you don’t have symptoms and it’s estimated this is true for half the women who have the condition.

It's also important to understand that BV isn’t a sexually transmitted infection (STI). However, it can put you at a higher risk of getting one. That’s why, as ever, you should always speak to your GP, or doctor or nurse at a sexual health clinic, if you have any concerns.

Triggers of bacterial vaginosis

There are several different bacterial vaginosis causes and factors that can upset your vagina's natural bacterial balance, potentially triggering BV. For example:

Hormonal changes (including pregnancy)
During your menstrual cycle, or when you’re pregnant, there are fluctuations in your hormones. These can affect what’s happening in your vagina and make you more susceptible to BV. So, if you do notice any unusual discharge or smell, let your doctor or midwife know.

Contraception (IUD)
Contraceptives such as the oral contraceptive pill, progesterone injections and condoms don’t increase your risk of BV. On the other hand, some women do notice changes after choosing to use an intrauterine device (IUD) which is often known as a ‘coil’. If that is the case for you, talk to your doctor, as BV can be treated without removing the device.

Medication
Certain medications, particularly antibiotics, can disrupt the natural balance of the bacteria in your vagina. This is because antibiotics don't just target the ‘bad’ bacteria, they can affect the ‘good’ ones too and this can also trigger BV.

Sexual activity
You can get BV without being sexually active. However, having new sexual partners or frequent sex can cause it (although it’s not understood why). It’s also more likely with same sex partners because it may be passed from woman to woman during sex.

Hygiene habits
A lot of women’s hygiene-related products might look great, but many can do more harm than good when it comes to BV. That’s why it’s best to avoid using them, particularly in a bath. If you have a choice, always wash in a shower and avoid potential irritants such as:

Heavily scented/perfumed soaps.
Scented/perfumed gels and shampoos.
Strong laundry powders and liquids for washing your underwear.

A vagina is a very sensitive part of your body and cleanses itself naturally. So also steer clear of certain products advertised or labelled as being ‘intimate’ or specifically for ‘feminine hygiene’. These can include:

Deodorants.
Washes.
Douches.

Bacterial vaginosis symptoms

It’s common to have BV and never show any symptoms at all. However, they’re easy to spot and here are the answers to the two most frequently asked questions:

What does bacterial vaginosis discharge look like?

A thin, watery discharge that’s a greyish-white colour.

Is there anything else I should look out for?

A smell usually described as being ‘fishy’. Specifically, after sex or during periods. It’s worth remembering that some discharge from your vagina is quite normal and is all part of the body’s ability to keep the vagina clean, healthy and infection-free. It’s also natural to see some changes if you’re on your period or during ovulation, and because you know your body better than anyone else, you’ll recognise these differences. For the same reason, you’ll probably know when everything’s fine and when something’s not quite right. Another important point is that unlike some vaginal infections, BV rarely causes soreness or itching. If you do experience these symptoms, it’s best to let your doctor know so they can check for other possible causes.

BV is also unlikely to cause cramps, cause pain or cause bleeding so, again, you should seek medical advice if this happens to you.

BV can sometimes be confused with thrush, but thrush is a very different condition. This is caused by a type of fungus called Candida albicans and is known as a yeast infection, which is usually harmless.

Thrush is a whole other subject. However, it’s good to know the main symptoms so you can easily recognise the difference between this and BV. Typically, with thrush:

You may notice a thick, white discharge that’s often described as looking like cottage cheese.
The condition, unlike many other vaginal infections, doesn't have an odour.
Your vaginal area and vulva are likely to become itchy and feel irritated.
Sex might become uncomfortable, and you may experience stinging or soreness when you urinate.
The affected area can become red, though this may be less noticeable if you have darker skin tones.

Although thrush isn’t an STI, it can be passed from men to women and vice versa. So if one sexual partner has symptoms, it’s worth the other person getting checked too.

What does bacterial vaginosis look like?

BV doesn't typically cause soreness or inflammation like some vaginal infections such as genital herpes. Which means you won’t see any lumps, bumps or sores. Again, if you do notice these, it’s likely to be something else and you should speak to your GP or go to your nearest sexual health clinic.

Does bacterial vaginosis cause infertility?

BV doesn't directly cause infertility, but if it’s left untreated during pregnancy there’s some risk your baby might be born prematurely or that you have a miscarriage. Although the risk is low, tell your doctor or midwife if you do recognise any of the symptoms of BV, particularly any usual vaginal discharge.

How is bacterial vaginosis diagnosed?

Your GP, or doctor or nurse at a sexual health clinic, can diagnose BV, usually by:

Discussing your symptoms and what you’ve noticed. This is always in complete confidence.
They might want to make a simple examination of your vagina or take a swab for testing. It’s quick, easy, and isn't painful.

Seeing someone in-person means you can talk to, and be diagnosed by, an experienced, understanding expert. It also provides an opportunity to talk about other possible conditions and test for them if needs be. The alternative, at least as a first step, is to test at home. You might also want to do this if you think you recognise the symptoms from a previous episode. You can get advice from a pharmacist and buy the test over the counter.

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Bacterial vaginosis treatment

BV will often go away on its own, particularly if you avoid the triggers. However, if symptoms are bothering you or you're pregnant, there are several treatment options. These include:

Antibiotic tablets.
Antibiotic gels or creams applied directly inside your vagina.

Treatment typically lasts between 5-7 days, and it can only be prescribed by a doctor or a sexual health clinic. Once you’ve got the medicine, you can take it or apply it at home. Even after treatment, BV can come back and if this happens to you, there are prevention strategies and, if needed, longer-term treatment options available.

How to prevent BV

When it comes to prevention, there are some simple, easy to adopt things you can do. Such as:

Avoid scented intimate products.
Don’t douche.
Shower rather than bath and only use water and plain soap to wash just the outside of your genital area.
Wipe from front to back after using the toilet.
Wear cotton rather than nylon underwear.

Sweat and tight-fitting clothing, particularly when they’re combined, can lead to bacteria too. So although it might sound obvious, it's important to change out of workout clothes like yoga pants, jogging bottoms or other gym gear as soon as possible after you’ve exercised and take a shower. Whilst it’s true that BV can be frustrating, it's very common, is usually easy to treat (if it needs treating at all) and often clears up in just a few days. It’s certainly nothing to feel embarrassed about either. Which is why, if you do notice an unusual discharge or odour, you should speak to your doctor or just go to a sexual health clinic. They're there to help.