Periods and the menstrual cycle

A period is when a woman bleeds from her vagina for a few days each month.

Periods are part of the menstrual cycle, which happens to prepare the body for pregnancy. Each month your ovary releases an egg. If that egg remains unfertilised (is not met by a sperm) the lining that was growing in the womb (uterus) to house a fertilised egg will leave the body – this is what a period is.

Women lose around 5 to 12 teaspoons of blood during each period. This might sound like a lot but it’s completely normal!

When the body is ready. Most girls start their periods when they are about 12, but they can start as young as 8 or as old as 16.

When a woman reaches the age of 45‒55, her periods will gradually stop. This phase is called menopause.

The timings for each stage will vary from person to person.

Day 1-5: Period. The first day of the cycle starts on the first day of a woman's period.

Days 5-14: When a period finishes, the womb will start to prepare for a fertilised egg. At around day 12-14, a new egg is released from an ovary (there are two ovaries in the body). These are the days when pregnancy is most likely to happen. But pregnancy can happen any time live sperm meets a live egg.

Days 15-24: The egg travels down the fallopian tube to arrive in the womb, and the womb gets ready to receive the egg by growing a thick lining for the egg to be implanted into.


Days 25-28: If the egg has been fertilised, it will implant into the lining and start to grow into a foetus. This means someone is pregnant and their periods will stop for as long as they are pregnant. But if the egg hasn’t been fertilised it will start to break down and so will the lining. The lining will then be ready to leave the body. And the cycle begins again.

Starting your period does not mean you are ready to have sex. Only YOU can decide whether you’re ready, and you should base this on what you think and feel. No one should ever pressure you into having sex.

Not necessarily. But you may experience changes in your cycle when you start or stop using some types of contraceptives, such as:

• the pill
• the implant
• the injection
• some IUDs.

If you don’t use contraception you can get pregnant at any time during your menstrual cycle, even during or just after your period.

You have the highest chance of getting pregnant (called being ‘fertile’) on the day your ovary releases an egg (called ovulation) and the days around it. If a live egg meets live sperm a pregnancy will happen. Your egg lives for about one day after ovulation, and sperm can live in your uterus (womb) and fallopian tubes for up to seven days after sex.

Some people have very regular cycles, but other people don’t. When you first start your periods they are likely to be irregular. This can make it hard to predict when your period will arrive and when you are likely to be most fertile.

If you don’t want to get pregnant you need to use contraception (birth control). And remember – only condoms protect against pregnancy and STIs, including HIV.

Don’t panic! It is normal for periods to arrive a few days earlier or later than expected.

But if you have had sex and your period is more than a week late it is a good idea to take a pregnancy test. If you don't want to wait until you've missed your period, you should wait at least one to two weeks after you had sex.