Milton Keynes 0-19 Service


What happens during a period?

When a girl starts going through puberty, she will start having periods. The average age for a girl to start having periods is 12 years old. However, because everyone’s different, it’s possible to start earlier or later than this.

A period happens when an egg is released from a female’s ovaries. When the egg is not needed, it is naturally removed from the body through the vagina.

When this happens blood comes out of the vagina for a number of days. It is possible to bleed from around three to eight days but everyone is different so some people bleed for a longer or shorter time than other people.

By the age of 18, females tend to have a period around once a month. On average, about 30 - 72 millilitres (two to four tablespoons) of blood is released during a period. Some people can bleed more or less than this amount.

What is a menstrual cycle?

Having a period can also be known as menstruation and is part of a female’s menstrual cycle.

Most females have their periods once a month and this is described as a menstrual cycle because it is a cycle that continues until a female’s period stops when she’s older.

The menstrual cycle is from the first day of your period until the day before your next period. The average length of the menstrual cycle is 28 days but anything between 24 and 35 days is common.

When girls first start having periods, they might not have them regularly but as they get older, it is likely that their periods will get more regular and every girl will get to know her own menstrual cycle.

How might I feel while having a period?

Before and during your period, there are changes to the levels of your hormones, which could cause you to feel differently. For example, you could experience changes to your moods, known as mood swings. It’s also possible to feel different physically, for example, some girls may get cramps, feel unwell and bloated, and their breasts could feel tender.

These feelings might not last for the whole time that you’re on your period and if you do experience some of these feelings, there are things that you can do to help you feel better.

If you have cramps, you could try to exercise or have a bath to help to warm up and relax your muscles, which can help you feel better. If you want to find out more about other things you can do to feel better, you can speak to an adult you trust or your school nurse for advice.

Will I ever stop having periods?

Your periods will continue until you reach the menopause. This is when your ovaries stop releasing eggs. This is a natural part of ageing and it usually happens between the ages of 45 and 55.

What are sanitary products?

Sanitary products absorb or collect the blood released during your period. It’s very important to change your sanitary products regularly to avoid becoming unwell.

There are different types of sanitary products including pads (also known as sanitary towels) and tampons.

Pads (Sanitary towels)

These are pads that are used to collect some of the blood that is released during your period.

One side of the pad is sticky so that you can attach it to your underwear. The other side is made out of special material that collects the blood. Many girls use pads when they start their periods because they can be used easily.

They come in many different types and sizes, so you can choose which ones you want to use depending on how comfortable they feel and how much blood is released during your period.

Some pads also have extra material on the sides called ‘wings’, you can fold the wings over the edges of your underwear to help hold the pad in place. Sometimes you might see pads that have fragrances but it’s important to know that fragranced pads can irritate the vagina so they might not be right for you.

You should change your pads regularly. How often you change them depends on how much blood is released when you have your period. On average, we recommend that you should change your pad around every four hours.


Tampons are small tubes made out of special material that can absorb the blood that has been released during your period.

Tampons are inserted into the vagina so that they can collect the blood before it comes out of the vagina. Many girls prefer to start using tampons when they get older and more mature because they are more difficult to use than pads.

Also, you are not likely to need to use tampons when you first start your period because you will have a lighter flow of blood.

There is a string is attached to the end of the tampon which you pull to remove it from the vagina. It is very difficult for this string to detach. It is also very rare for a tampon to get lost or stuck inside because the vagina holds it firmly in place. Tampons come with instructions that explain how to use them and if the tampon is inserted correctly, you shouldn't be able to feel it.

If you can feel it or it hurts, it might not be in properly or it’s possible that the type of tampon is not correct for you. You should try again with a new tampon or consider using a different type of sanitary product.

Panty liners

Panty liners are a much smaller and thinner type of pad. They can be used to collect vaginal discharge, which is a cream-coloured fluid that can come out of the vagina every day.

It is common to get vaginal discharge once you have started puberty and it is usually a sign that your vagina is cleaning itself. They can also be used on days when your period is very light.

You should change your panty liner once it begins to look or feel moist.

Why do I need to change my sanitary products?

Sanitary products should be changed regularly because if you don’t change them, you might become unwell due bacteria that builds up from the blood. This can be very serious and dangerous for your health.

This information has been provided by our school nurses and NHS Choices.