You lose about 4 tablespoons of liquid during a menstrual period – less than a decilitre, in other words! The amount of blood that you lose is individual, so 2 tablespoons or 1 ½ decilitres is normal too. If you bleed very heavily, you can become anaemic (a shortage of iron) and should talk to a gynaecologist, school nurse, or a doctor at a young person’s clinic. Find out more about periods. Read our article entitled “Periods – a basic course.”