Your menstrual cycle

One of the reasons it’s wise to use contraception is to prevent an unplanned pregnancy. That’s why it makes sense to understand your menstrual cycle, especially if you're going to use hormonal contraceptives like the birth control pill.


Smart tip: If you opt for the birth control pill,
you still need to protect yourself against sexually transmitted infections (STIs)
So speak to your healthcare professional about your best options!


Understanding your menstrual cycle

Your menstrual cycle is a natural process that prepares your body for pregnancy. The female sex hormones (oestrogen and progesterone), together with hormones produced by the pituitary gland (luteinising hormone and follicle-stimulating hormone), control the whole process.  They trigger the development of an egg and, during a process called ‘ovulation’, the egg is released from your ovary.

At the same time, the lining of your uterus (womb) changes to become thicker to prepare your womb for receiving the fertilised egg. If you don’t become pregnant in that cycle, the lining of the womb disintegrates and is shed in menstruation or your ‘period’. Your menstrual cycle takes about 28 days, but it can vary anywhere between 21 to 38 days.

The 4 stages in your menstrual cycle

  • Menstruation
    The day you get your period (the bleeding starts) is the first day of your menstrual cycle.
  • Pre-ovulatory
    Your body prepares for ovulation and the release of an egg. Oestrogen levels increase and the womb lining thickens.
  • Ovulation
    Ovulation is the release of the egg from the ovary. Most pregnancies occur if you have sex within 3 days before ovulation, so this is the time when you're most likely to become pregnant if you’re NOT on the Pill or using contraception. If the egg is not fertilised by a sperm cell, it degenerates after 14 days and is expelled with your next period.
    If the egg is fertilised by a sperm cell, it (now called an embryo) travels to the womb, is implanted there and develops into a baby during the next nine months.
  • Post-ovulatory
    The lead-up to menstruation lasts 14 days on average and finishes the cycle. You then have your period and the cycle starts all over again.