Why your flares show up around your period

If your symptoms seem to have a calendar, you’re probably right. A lot of women notice it before any doctor mentions it: BV odour that gets stronger during or just after a period, or yeast that shows up in the days before one.

Your vagina isn’t the same environment all month. Here’s why.

Blood changes the pH

A healthy vagina is slightly acidic — that low pH is one of its main defences, and lactobacilli keep it there. Blood is not acidic. During your period, the pH rises, and that briefly gives the bacteria linked to BV a better environment to grow in.

That’s also why many women notice BV odour most during their period and after sex — semen is alkaline too.

Hormones change the terrain

Across the cycle, oestrogen and progesterone rise and fall, and the vaginal environment shifts with them. Many women notice yeast symptoms in the second half of their cycle, in the run-up to their period.

There’s a lookalike worth knowing about here too: cytolytic vaginosis — an overgrowth of lactobacilli — also tends to flare before a period, with itching and burning that feels like yeast but doesn’t respond to antifungals.

What to do with this

• Track your cycle day alongside your symptoms. If flares keep landing on the same days, write that down and bring it to your appointment. A pattern is information.
• Look at your period products. Scented pads and liners are a common irritant. Change tampons and pads regularly, and if you use a menstrual cup, clean it well between cycles.
• Don’t reach for a wash. The urge to “freshen up” during your period is exactly when your flora is most vulnerable to soaps and intimate washes.

Your cycle isn’t the problem. But it can tell you a lot about what is.