Question: how much blood is lost during a normal menstrual cycle?
Answer: Most women will lose less than 16 teaspoons of blood (80ml) during their period, with the average being around 6 to 8 teaspoons. Heavy menstrual bleeding is defined as losing 80ml or more in each period, having periods that last longer than 7 days, or both. But it's not usually necessary to measure blood loss.