The amount of blood you lose during a period varies from woman to woman, like most aspects of your monthly cycle.
About two to three tablespoons of blood is average throughout your whole period. But remember – it looks like more than it is. So what might seem like a particularly heavy menstrual flow amount could actually be completely normal. And don’t forget that once you start your periods it takes a while for them to become regular.
Periods are considered heavy if there is enough blood to soak a pad every hour for several consecutive hours. Other symptoms of heavy periods include passing large blood clots during menstruation or finding blood on your clothing or bedding.
Factors that affect the amount you bleed are stress levels, diet, hormone levels, choice of contraception and hereditary reasons. Plus, whether or not you’ve given birth. If you’re worried that you’re experiencing abnormal periods, discuss it with your doctor or school nurse.