Postmenopausal bleeding means any bleeding that happens 12 months or more after your last period. Most cases turn out to have a benign cause, such as thinning of the vaginal or womb lining, polyps, or an effect of HRT. However, because it can also be an early sign of womb (endometrial) cancer, it should never be ignored.
The reassuring point is that when serious causes are found early, they are usually very treatable. That is exactly why prompt assessment matters, rather than waiting to see if it stops.
Book an appointment as soon as possible if you have any bleeding or spotting after menopause, even if it is light or happens only once. The clinician may examine you and arrange tests such as an ultrasound to find the cause and give you peace of mind.