Heavy menstrual bleeding (menorrhagia) is judged by its impact more than an exact volume. Warning signs include flooding through clothing, doubling up on protection, frequently changing products every hour or two for several hours, passing large clots, periods lasting longer than about 8 days, and symptoms of low iron such as tiredness, breathlessness, or pale skin.
Heavy bleeding has many possible causes including fibroids, polyps, hormonal imbalance, certain contraceptive devices, thyroid problems, and bleeding disorders. It is common and very treatable, so it is worth raising even if you have lived with it for years.
Seek urgent care if you are soaking through protection every hour for several hours, feel faint or dizzy, have a racing heart, or have very sudden severe bleeding. Otherwise, book a routine appointment so a clinician can check your iron levels and look for an underlying cause.