Menstruation

What is menstruation?

  • Menstruation - having periods - is part of the reproductive cycle for those with a female anatomy that starts when they become sexually mature at the time of puberty.
  • During a menstrual period, a person bleed from the uterus (womb) via the vagina. This lasts anywhere from three to seven days.
  • Each period commences approximately every 28 days if a person does not become pregnant during a given cycle.


Why do we menstruate?
The internal sex organs consist of two ovaries, the Fallopian tubes, the uterus (womb) and the vagina. The ovaries contain the eggs with which every person with a typical female anatomy and physiology is born, and, during each period, a single egg will usually ripen and mature due to the action of hormones circulating in the bloodstream.

Menstruation is a very complicated process involving many different hormones, the sex organs, and the brain. The Follicle Stimulating Hormone (FSH) causes an egg to mature in an ovary and stimulates the ovaries to release the hormone oestrogen. Oestrogen then stops further FSH from being produced (to stop another egg from being released), and stimulates the pituitary gland to release Luteinising hormone, which in turn stimulates the ovary to release the egg. When the egg is mature it bursts from the ovary and drifts through the Fallopian tube down into the uterus. The lining of the uterus - the endometrium - has been thickened by the action of progesterone and made ready to receive the fertilised egg.

If the egg is fertilised and pregnancy occurs, it will fasten itself onto the endometrium. If the egg is not fertilised, however, resultant hormonal changes cause the endometrium to slip away and menstruation begins. Menstrual discharge is composed of the endometrium itself, together with a little fresh blood caused by the breaking of very fine blood vessels within the endometrium as it detaches itself from the inside of the uterus. The amount of blood lost due to the normal monthly period is usually less than 80ml.

The menstrual cycle
The menstrual cycle can last between 21 and 40 days. However, the length from month to month may vary from one person to another. A period usually lasts between two to eight days.

When does menstruation begin?
Menstruation begins between the ages of 10 and 16. The average age is approximately 12. Menstruation continues until the ages of 45 to 55, when menopause begins. There are approximately 500 periods in a lifetime.