Worksheet 3: The Menstrual Cycle

Days:1-7

The period is considered the beginning of the menstrual cycle. A period normally lasts for around five days, but can be as short as two days or as long as seven. There will usually be around 2-6 tablespoons of blood lost during each period, depending on the heaviness of the flow. A period occurs because the uterus will shed its lining if an egg (ovum) is not fertilised.

Days:8-14

One of the ovaries releases an egg and the uterus begins to rebuild its lining. Only one egg is released each cycle. The egg will slowly travel down the fallopian tube from the ovaries towards the uterus. If the egg is fertilised by a sperm before it arrives in the uterus, a girl will fall pregnant.

Days:15-28

If the egg isn’t fertilised, the uterus wall will continue to thicken until there is a sudden drop in hormone levels. The lining will then break down, and another period will begin.