The symptom list most GPs and most articles lead with is the same six: hot flushes, irregular periods, night sweats, mood changes, vaginal dryness, sleep problems. It's accurate. It's also not complete. Bleeding heavy enough to soak through protection within the hour, bleeding that doesn't stop for weeks, bleeding that means planning a day around bathroom access — flooding is common in perimenopause and rarely named on the list that's supposed to cover it.

What counts as flooding

There's no single clinical threshold that separates a heavy period from flooding, but the pattern is recognisable: soaking through a pad or tampon within an hour, passing clots larger than a 10p coin, or needing to change protection through the night. If a period is dictating what you can do that day, it's worth naming as flooding rather than filing under heavy periods, as usual.

The mechanism

Perimenopausal cycles are often anovulatory — no egg is released that month. Ovulation is what triggers progesterone production, and progesterone's job is to balance that month's oestrogen and stabilise the womb lining. Without it, oestrogen goes unopposed: the lining builds up for longer than usual, then sheds unpredictably and heavily when it finally does. This is a mechanical, hormonal explanation, not a mystery and not a personal failing of the body.

Why it's missed

Symptom lists that lead with hot flushes and irregular periods use "irregular" as a catch-all, and catch-alls undersell what they're covering. Irregular can mean a period that arrives four days early. It can also mean bleeding through clothing in a work meeting. Both are technically irregular periods. Only one of them tends to get filed under normal perimenopause without a second thought.

When to get it checked

NICE guidance (NG23) is specific here: a bleeding pattern that changes significantly, doesn't settle, or occurs after sex or between periods should be assessed, not assumed to be an inevitable part of the transition. Assessment exists to rule out other causes — fibroids, polyps, thyroid issues, and less commonly, endometrial changes that need a different kind of attention. Getting it checked isn't second-guessing a perimenopause diagnosis. The two aren't in competition.

What assessment usually involves

What a GP does next depends on the presentation, but a first conversation typically covers bleeding pattern and duration, associated symptoms, and iron levels — heavy bleeding over time can lead to iron-deficiency anaemia even without other symptoms flagging it. Depending on the picture, that conversation may lead to a blood test, a pelvic ultrasound, or a referral, not because something is necessarily wrong, but because "wait and see" isn't the guidance for a bleeding pattern that's changed shape.

The point of naming it

None of this requires the bleeding to be dramatic before it's worth mentioning. A pattern that's changed enough to notice is itself the signal NICE guidance points to — not a certain volume, not a certain number of soaked pads. Worth raising with a GP as its own topic, specifically, rather than folded into a general sense that perimenopause is rough at the moment.