What Happens If You Leave BV Too Long?

"Leaving it too long" isn't a fixed deadline, it's more about how BV behaves over time and how to recognise when it's stopped being a minor, self-resolving thing. Here's the actual timeline: how long BV can hang around untreated, how long treatment takes to work, and when the clock genuinely matters.

How long does BV last if you don't treat it?

It varies a lot. Some cases resolve without any treatment at all, roughly estimated at around 3 in 10, but there's no reliable way to know in advance whether yours will be one of them. Left alone, BV commonly persists for weeks, and in a meaningful number of cases, months, with symptoms like discharge, odour and irritation continuing or gradually getting worse rather than settling down. Waiting it out is a genuine gamble rather than a safe default.

How long does treatment actually take?

With a standard prescribed course, usually metronidazole tablets or gel over 5 to 7 days (sometimes a single higher dose), most people see their symptoms clear within about a week. It's a fast turnaround once you're on the right treatment, which is part of why there's little upside to delaying a GP or sexual health clinic visit once you suspect BV rather than waiting to see what happens.

Why BV comes back even after it clears

Recurrence is common and doesn't necessarily mean you've "left it too long" the first time. Around 1 in 10 to 15 people need a second course of treatment after the first doesn't fully clear things, and it's well documented that about half of women who get BV will have it again within 6 to 12 months, even when it was properly treated the first time. Some of that is the same infection never quite clearing; some of it is a fresh episode triggered by the same conditions that caused it originally, including, in some cases, a regular sexual partner. We've covered the research on why partners may play a role in recurrence in Who Is Most Likely To Get BV?

Signs it's gone on too long

A few thresholds are worth knowing so you're not just guessing:

• Symptoms that haven't started improving within about 3 days of starting treatment
• Symptoms that are still present a full week after starting treatment
• Untreated symptoms that have been going on for more than a week or two with no sign of settling
• New symptoms like fever, pelvic pain, or pain that feels different from your usual BV discomfort, which can be a sign of a developing complication rather than straightforward BV

Any of these are a reasonable trigger to go back to a GP or sexual health clinic rather than waiting it out further or trying another round of the same self-treatment.

What's actually at stake the longer it goes on

This isn't about panic, most people who get BV treated within a reasonable window have no lasting issues at all, but genuinely prolonged, untreated BV is where the more serious risks (increased susceptibility to other infections, pelvic inflammatory disease, pregnancy complications) start to become relevant rather than theoretical. We've covered that full list separately in What does untreated BV lead to? so this article can stay focused on timing rather than repeating it here.

If you're trying to stop BV coming back once it's cleared, we've looked at what the evidence actually says about probiotics and ongoing prevention in Can I Get Rid Of BV By Taking Probiotics?