No. BV is not a sexually transmitted infection. It's caused by an imbalance of bacteria that naturally live in the vagina — Lactobacillus bacteria decrease while other bacteria (like Gardnerella vaginalis) overgrow. However, sexual activity (especially with a new partner or multiple partners) can disrupt the vaginal microbiome and increase the risk of developing BV.

Bacterial Vaginosis (BV): Symptoms, Causes & Treatment

Q: What are the main symptoms of BV?

The most common symptoms of bacterial vaginosis are: thin, watery discharge that is white, grey, or off-white; a strong fishy odour, especially after sex; and mild itching or burning. Around 50% of women with BV have no symptoms at all, which is why regular testing is important.

Q: What does BV discharge look like?

BV discharge is typically thin, watery, and greyish-white or off-white. It's different from yeast infection discharge (which is thick and clumpy) and from normal discharge (which is clear to milky and odourless). The most distinctive feature of BV is the fishy smell.

Q: Can BV go away on its own?

BV sometimes resolves on its own, but it commonly returns without treatment. Untreated BV also increases the risk of STIs, pelvic inflammatory disease, and complications in pregnancy. Most doctors recommend treating BV with antibiotics (metronidazole or clindamycin) to clear it and reduce health risks.

Bacterial vaginosis (BV) is a condition caused by an imbalance of bacteria in the vagina. Normally, beneficial Lactobacillus bacteria dominate and keep the vaginal pH acidic. With BV, these good bacteria are reduced and replaced by an overgrowth of other bacteria — most commonly Gardnerella vaginalis and others. It's the most common vaginal condition in women aged 15–44.

~50%

of women with BV have no symptoms at all

1 in 3

women will experience BV at some point

50–70%

recurrence rate within 12 months of treatment

Symptoms of BV

When symptoms do occur, they typically include:

Unusual discharge — thin, watery, and greyish-white or off-white in colour
Fishy odour — often strong and unpleasant; typically worse after sex or after your period
Itching or irritation — around the vulva (less pronounced than with a yeast infection)
Burning sensation — when urinating
No symptoms — around 50% of women with BV feel completely normal

The telltale sign: The fishy smell is the most distinctive feature of BV — especially noticeable after sex, because semen raises vaginal pH, which intensifies the odour. This odour is absent in yeast infections.

BV vs. Yeast Infection — Key Differences

	Bacterial Vaginosis	Yeast Infection
Discharge	Thin, watery, grey/white	Thick, clumpy, white
Odour	Strong, fishy — especially after sex	None or very mild
Itching	Mild or absent	Intense
Redness	Usually absent	Common
Treatment	Antibiotics (metronidazole, clindamycin)	Antifungal (fluconazole, clotrimazole)

What Causes BV?

BV is caused by an imbalance in the vaginal microbiome — it's not a traditional "infection" caught from another person. However, certain things disrupt the balance:

New or multiple sexual partners (changes vaginal bacteria)
Douching or using scented vaginal products (destroys good bacteria)
Antibiotics (kill Lactobacillus alongside other bacteria)
Smoking
Using an IUD (higher rate of BV in IUD users, especially hormonal IUDs)
Hormonal changes (pregnancy, menopause)
Unprotected sex with female partners

Treatment

✓ Prescription antibiotics clear BV

Metronidazole — most commonly prescribed. Available as tablets (taken orally 2x/day for 7 days) or gel (inserted vaginally for 5 days). Avoid alcohol during treatment.
Clindamycin cream — inserted vaginally for 7 days. A good option if metronidazole isn't tolerated.
Single-dose options — some doctors prescribe a single 2g dose of metronidazole, though the 7-day course has a higher success rate.

BV cannot be treated with over-the-counter antifungal products — these only work for yeast infections. See a doctor or visit a sexual health clinic to get tested and prescribed the right treatment.

Why Does BV Keep Coming Back?

BV has a high recurrence rate — up to 70% of women experience it again within a year of successful treatment. This is because antibiotics clear the overgrown bacteria but don't reliably restore healthy Lactobacillus populations. Strategies that may help reduce recurrence include:

Avoiding douching entirely
Using condoms consistently
Wearing breathable cotton underwear
Taking oral or vaginal probiotics containing Lactobacillus (evidence is mixed but some women find them helpful)
Discussing longer-term maintenance antibiotics with your doctor if BV is very recurrent

BV and Pregnancy

⚠ BV in pregnancy carries added risks

Untreated BV during pregnancy is associated with increased risk of preterm birth, low birth weight, and late miscarriage. If you're pregnant and have any BV symptoms, speak to your midwife or GP promptly. BV is safely treated with antibiotics in pregnancy.

Track Your Cycle and Symptoms

Log discharge, odour changes, and other symptoms alongside your cycle. Spotting patterns in WomensPal can help you identify triggers and know when something's changed.

Start tracking free →

Frequently Asked Questions

What are the main symptoms of BV?

The most common symptoms are thin, watery grey or white discharge, and a strong fishy odour (especially after sex). Around half of women with BV have no symptoms at all.

What does BV discharge look like?

BV discharge is typically thin, watery, and greyish-white. It's different from yeast infection discharge (thick and clumpy) and from normal discharge. The fishy smell is the most distinctive feature.

Can BV go away on its own?

Sometimes, but most doctors recommend treatment with antibiotics to clear it and reduce risks — especially in pregnancy, where untreated BV can increase the risk of preterm birth.

Is BV an STI?

No. BV is not sexually transmitted — it's caused by an imbalance of bacteria that naturally live in the vagina. However, sexual activity can disrupt the vaginal microbiome and increase the risk of developing BV.