Most gynaecological symptoms have a reasonable window in which watching and waiting is sensible. One does not, and guidance around the world agrees on it: vaginal bleeding that happens more than a year after your last period.
The reason is not that most causes are serious. In fact the most common causes are not cancer at all — a thinned vaginal lining from low oestrogen, a polyp in the womb or cervix, or a side effect of certain medicines. Those are treatable and not dangerous. The reason it is always assessed is that bleeding after menopause is the first and often the only symptom of endometrial cancer, which has very good outcomes when found early.
What most often delays women is how little blood there is. Many see a single faint brown spot that never returns and assume it cannot matter. But the amount does not track with the significance. A single episode meets the threshold for assessment just as heavy bleeding does.
Assessment usually begins with your history, an internal examination, and a transvaginal ultrasound to measure the thickness of the womb lining. If the lining is thicker than expected or something else needs a closer look, a sample of the lining may be taken — a short procedure that can be done in an outpatient setting. The whole pathway is often complete within one or two appointments.
See a doctor for any vaginal bleeding occurring more than a year after your last period, even a single spot that does not return, and go sooner if the bleeding is heavy, comes with lower abdominal pain, or there is blood-stained discharge that persists.