The Menstrual Cycle

Menstruation is a process which repeats its cycle every month or so. The menstrual cycle refers to the changes that happen in the body that result in menstruation. Your menstrual cycle includes your period, as well as other hormonal changes. We start counting the days of your menstrual cycle from the first day of your period; this is ‘Day 1’.


Your menstrual period (when you are bleeding) usually lasts between 2-7 days.

It’s common for your menstrual cycle to be a bit irregular in the first few years of your period, so some months it might be longer or shorter by up to as much as a week. This usually resolves in a few years and your period will start to come more regularly.  It’s common to get a period about every 28 days but it is normal to range anywhere from 21-35 days. If you find your menstrual cycle is lasting longer than 35 days on a regular basis, speak with your doctor about it.

  • Menstruation is important for reproduction (when a baby is made).
  • The menstrual cycle is an on-going process of ovulation (producing and releasing an egg (ovum) from the ovary).
  • The lining of the uterus (womb) thickens in preparation for a possible pregnancy.
  • If an egg is not fertilised, then this lining is shed as blood and tissue (your period).

Watch this short clip to hear Dr Kelly Parry explain how the menstrual cycle works: