Your ‘Menstrual cycle’ can start anytime from the age of 8 to 18 and will be a part of your life until you reach your 50s. As you will continue to have your periods for many years, it’s worth understanding what’s going on so you can make sure you’re the one in control.

How long is my menstrual cycle?

You’ll often hear that your cycle lasts 28 days. In all honesty it varies a lot, from month to month and person to person. Anywhere from 21 to 34 is common.

Click on the video to see what’s going on during your cycle.

28 Days of your cycle

Menstrual Phase

Days 1 - 5

Day 1 marks the start of your period. It’s when you (or your uterus to be precise) release a mixture of blood and nutrients out of your body, which can vary in colour and texture.

Although you may feel like there’s quite a bit of blood, in reality you'll only lose between 10 - 80 ml. A period usually lasts between 2 - 5 days but could be up to 10. The majority of blood loss occurs during the first 2 days and some women notice menstrual (abdominal) cramps, back and leg ache too.

Follicular Phase

Days 6 - 13

More oestrogen is produced at this stage and your ovaries prepare to release an egg. Your body also prepares for pregnancy so the lining (we’re talking about your uterus again) starts to develop. This is the most unpredictable part of your cycle and the reason why your cycle can be longer or shorter than the stated 28 days you'll often hear about.


Day 14

About half way through your cycle, one of your ovaries releases a miniscule egg, which journeys down your fallopian tube where fertilisation takes place.

The sperm has a small window of around 48 hours to fertilise the egg before the unfertilised egg is absorbed back into the body. The 6 days leading up to this and the 2 days after this event is when you’re most fertile and you could become pregnant if no birth control is used at this time.

Luteal Phase

Days 15 - 28

The final stage before your period starts again.

This lasts for 14 days while your body produces more oestrogen and progesterone, which causes the lining of your uterus (you’re back here again) to thicken with blood and nutrients.

If you're not pregnant, progesterone levels drop which causes the lining to break-up and your cycle starts all over again.