What is the menstrual cycle?
The menstrual cycle is a series of monthly changes in the female reproductive system that prepares the body for a possible pregnancy. It usually lasts about 28 days, though this can be a little shorter or longer for different people.
The main stages
- Menstruation (period) — the lining of the uterus breaks down and leaves the body as blood through the vagina. This lasts about 3 to 7 days.
- Repair and thickening — after the period, the lining of the uterus grows thick again, ready to receive a fertilised ovum.
- Ovulation — around the middle of the cycle (about day 14), an ovary releases a mature ovum.
- Waiting — the ovum travels along the oviduct. If it is not fertilised, the thick lining is not needed and breaks down, so the next period begins.
Key idea
A menstrual cycle is about 28 days. Ovulation (release of the ovum) happens around day 14. If the ovum is not fertilised, menstruation occurs.
Why it matters
The menstrual cycle shows that the body is healthy and able to reproduce. It is a normal and natural part of growing up for girls, usually starting during the teenage years.
Remember
- The cycle is about 28 days.
- Ovulation is the release of an ovum, around day 14.
- If the ovum is not fertilised, menstruation happens.