Bacterial vaginosis
Also called: BV, vaginal bacterial imbalance, fishy-smelling vaginal discharge, Gardnerella infection
Bacterial vaginosis (BV) is a common change in the balance of bacteria in the vagina. It can cause a thin, grey-white discharge with a fishy smell, but many women have no symptoms. It is not a sexually transmitted infection, and antibiotics usually clear it.
General health information for Pakistan. It does not give doses or brand advice. If you are worried, or symptoms are severe, see a doctor. When to see a doctor
Overview
Bacterial vaginosis (BV) is one of the most common causes of unusual vaginal discharge in women of child-bearing age. Normally the vagina is kept healthy by friendly bacteria called lactobacilli, which keep it slightly acidic. In BV these are pushed out by an overgrowth of other bacteria, such as Gardnerella. Doctors do not fully know what starts this change. The World Health Organization estimates that roughly a quarter of women of reproductive age worldwide have BV at any time.
About half of women with BV notice nothing at all. Others get a thin, watery, grey-white discharge with a strong fishy smell, often worse after sex. BV is not counted as a sexually transmitted infection (STI), and women who have never had sex can get it. However, sex can trigger it, and it makes it easier to catch STIs, including HIV.
BV is usually easy to treat with antibiotic tablets, gel or cream prescribed by a doctor. It often comes back within a few months, so it helps to avoid triggers such as douching (washing inside the vagina) and perfumed products. If you are pregnant and your discharge changes, see your doctor or midwife, because BV can sometimes affect pregnancy.
In Pakistan
A study of 100 women of child-bearing age with vaginal discharge, published in the Journal of Rawalpindi Medical College by a Karachi-based researcher, found BV in 39% and showed that simple pH and whiff tests can help diagnose it where laboratory facilities are limited.
Symptoms
- No symptoms at all in about half of women
- A thin, watery vaginal discharge that may look grey or off-white
- A strong fishy or musty smell, often more noticeable after sex
- More discharge than usual for you
- Mild itching or irritation around the vagina in some women, although BV usually does not cause soreness or itching
- A burning feeling when passing urine in some women
Causes and risk factors
Causes
- A change in the natural balance of bacteria in the vagina, where protective lactobacilli are replaced by other bacteria such as Gardnerella and Prevotella
- Loss of the normal acidity of the vagina, which weakens its natural defences
- Triggers such as douching, inserting herbs or other products into the vagina, or sex with a new partner; the exact cause is not fully known
- BV is not caused by poor hygiene and is not classed as a sexually transmitted infection
What makes it more likely
- Having a new sexual partner or more than one partner
- Not using condoms consistently
- Douching or washing inside the vagina
- Putting herbs, cloths or other products inside the vagina
- Using perfumed soaps, bubble bath, vaginal deodorants or washes
- Having a copper intrauterine device (coil, IUD)
- Having genital herpes (HSV-2) infection
- Having BV before, as it often comes back
Complications
BV does not usually cause serious problems, but it should not be ignored. It makes it easier to catch sexually transmitted infections such as chlamydia, gonorrhoea, trichomoniasis, genital herpes and HIV, and to pass HIV on. Untreated BV is linked with pelvic inflammatory disease (infection of the womb and fallopian tubes) and with infections after gynaecological surgery. In pregnancy, BV with symptoms is linked with miscarriage, early breaking of the waters, preterm (early) birth, infection of the fluid around the baby and infection of the womb after delivery. Most pregnant women with BV still have no problems. BV also comes back often, which can be upsetting.
When to see a doctor
- You are pregnant and your vaginal discharge changes or smells unusual: see your doctor or midwife promptly
- You are pregnant and fluid leaks from your vagina, or you have tightening or period-like pains before your due date: go to hospital straight away
- Fever, pain in the lower tummy or pelvis, or bleeding along with the discharge, which are not typical of BV and need checking
- You may have been exposed to a sexually transmitted infection, for example a new partner or a partner with symptoms
- Symptoms that do not clear after treatment or come back soon after
- BV that comes back more than four times a year
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Diagnosis
A doctor, nurse or sexual health clinic will ask about your symptoms and may look inside the vagina. A swab (like a long cotton bud) is wiped over the discharge and checked for BV and other infections such as thrush, trichomoniasis and other sexually transmitted infections.
In the clinic, BV is often diagnosed when at least three of four signs are found: thin, even discharge; a vaginal pH (acidity) above normal; a fishy smell when a test liquid is added to the discharge (whiff test); and special cells called clue cells seen under a microscope. A laboratory may also use a stained slide (Gram stain), which is the reference test. Newer molecular tests can help in women with symptoms. Growing Gardnerella in culture and cervical smear (Pap) tests are not useful for diagnosing BV. Where laboratory tests are not available, WHO advises treating women with discharge based on their symptoms. All women with BV should be offered testing for HIV and other STIs.
Treatment
- See a doctor or sexual health clinic to confirm BV and rule out other infections, including sexually transmitted infections
- Treatment is recommended for women who have symptoms; women with no symptoms usually do not need routine testing or treatment
- Your doctor prescribes an antibiotic, usually metronidazole as tablets or vaginal gel, or clindamycin vaginal cream; your doctor decides which one, the dose and how long to use it
- Avoid sex, or use condoms correctly every time, until treatment is finished; clindamycin cream can weaken latex condoms and diaphragms for some days after use
- If BV comes back, another course of antibiotics is usually given; for frequent returns, a doctor may suggest using an antibiotic vaginal gel regularly for several months
- If you are pregnant or breastfeeding, tell your doctor or midwife, who will choose a medicine that is suitable; do not start or stop any medicine yourself
- Routine treatment of male partners is not recommended, but a female partner may also need to be checked and treated
Medicines in Pakistan
Medicines a doctor may use, by group. Read the role: some are only for special cases. Each link opens our page for that medicine, with every brand and its official DRAP price. Your doctor decides which medicine and dose are right for you.
| Group | Role | Medicines |
|---|---|---|
| Nitroimidazole antibiotics | metronidazole tablets or vaginal gel are a first choice; tinidazole is an alternative but should be avoided in pregnancy; metronidazole vaginal gel may also be used longer term to prevent frequent returns; your doctor decides which one and the dose | Metronidazole (258 brands), Tinidazole (5 brands) |
| Lincosamide antibiotics | clindamycin vaginal cream is a first choice, and clindamycin capsules or vaginal pessaries are alternatives; considered usable in pregnancy; the cream can weaken latex condoms and diaphragms; doctor decides | Clindamycin (42 brands) |
Also used (not yet in our price list): Secnidazole (an alternative nitroimidazole antibiotic; should be avoided in pregnancy)
Self-care and prevention
Self-care
- Wash the genital area with water and plain, unperfumed soap
- Have showers rather than baths if you can
- Do not douche or wash inside the vagina, and do not put herbs or other products inside it
- Avoid perfumed soaps, bubble bath, vaginal deodorants, vaginal washes and antiseptic liquids in the bath
- Wash underwear with a mild detergent
- Finish the full course of treatment, even if symptoms settle early
- Use condoms, which also protect against sexually transmitted infections
- Avoid smoking
Prevention
- Avoid douching and putting anything inside the vagina to clean it
- Avoid perfumed products in or around the vagina
- Use condoms consistently, especially with a new partner
- Ask your doctor about possible triggers, such as sex or your period, if BV keeps coming back
Common questions
Is bacterial vaginosis a sexually transmitted infection?
No, BV is not classed as an STI, and women who have never had sex can get it. But sex can trigger it, it can pass between female partners, and it raises the chance of catching an STI. That is why your doctor may offer STI and HIV tests.
Does my husband or male partner need treatment?
Usually not. Studies have found that treating male partners does not stop BV coming back. If your partner is a woman, she may need to be checked and treated as well.
Is bacterial vaginosis harmful in pregnancy?
Most pregnant women with BV have no problems, but BV with symptoms is linked with a small risk of miscarriage and early birth. If your discharge changes in pregnancy, see your doctor or midwife. Some antibiotics, such as tinidazole and secnidazole, should be avoided in pregnancy, so your doctor or midwife will choose the medicine.
Why does BV keep coming back?
BV often returns within a few months of treatment, and doctors do not fully understand why. Avoiding douching and perfumed products may help. If it returns more than four times a year, your doctor may suggest a longer course of antibiotic vaginal gel to keep it away.
Can probiotics or yoghurt cure BV?
There is no good evidence that probiotic or lactobacillus products treat BV or help when added to antibiotics. Antibiotics prescribed by a doctor remain the proven treatment.
Sources
- World Health Organization (fact sheet). Bacterial vaginosis (2025).
- Centers for Disease Control and Prevention (CDC), Sexually Transmitted Infections Treatment Guidelines, 2021. Bacterial Vaginosis - STI Treatment Guidelines (2021).
- NICE (National Guideline Alliance). Antenatal care: evidence reviews for management of symptomatic vaginal discharge in pregnancy (draft for consultation) (2021).
- NHS. Bacterial vaginosis (n.d.).
- NHS. Bacterial vaginosis (n.d.).
- Journal of Rawalpindi Medical College. Prevalence of Bacterial Vaginosis in Females of Child Bearing Age and Utility of pH and Whiff Test in Diagnosis (2020).
Prepared from the sources listed below by the MedInfoBase team. Last reviewed 16 October 2026. This page is general health information, not medical advice. It gives no doses and does not replace a doctor: talk to your doctor or pharmacist before starting, stopping or changing any medicine. How we write and check our pages.