What is a period?

Periods come about because the lining of the uterus breaks down and causes a small amount of bleeding from the vagina. This may sound frightening but if you are prepared then it is nothing to worry about! The blood trickles gradually over a few days and good-quality tampons or sanitary towels can easily cope with the flow. 

What is the menstrual cycle?

The menstrual cycle (the time in the month when your period comes) is controlled by hormones.

When the period starts, the hormone FSH from the pituitary gland in the brain is making and ovum (an egg) mature in a tiny sac called a follicle in one of the ovaries. When it is over a few days later, the ovum continues to mature and moves towards the surface of the ovary. It is producing the hormone oestrogen, which makes the lining of the uterus start to thicken again. At the moments it's about 1mm thick. About a week later the pituitary gland stops producing FSH and produces LH instead. This makes the mature ovum burst out of its follicle, leave the ovary (ovulation) and enter the fallopian tube. The empty follicle starts to produce progesterone, which makes the lining soft and spongy so that if the ovum is fertilized it can embed itself. A week later, if the ovum has not been fertilised then it starts to disintegrate and the levels of the hormones fall. The lining is now about 5mm thick. It starts to disintegrate and come away from the wall of the uterus. Some blood vessels tear in this process, which is why there is blood.

Why do girls have periods?

When girls are born, they have thousands of ‘eggs’ inside their ovaries. After reaching puberty (around 11 to 15 years) roughly every month, this is what happens:

• One egg bursts out of the ovary because of hormone changes in your body.
  
• It travels along to your womb via your fallopian tubes (the womb is where a baby would grow if the egg had been fertilized by a sperm.
  
• The wall of the womb gets thick, and ready, just in case a fertilized egg needs to grow there, every month.
  
• If the egg does not get fertilized by a man’s sperm, then the egg and the lining of the womb, come away.
  
• They come out through the woman’s vagina - but don’t expect to see the egg because it is less than the size of a pinhead and is all mixed up with the blood.

When can girls start their periods?

95% of girls start having their periods between the ages of 11 and 15. The others may start as young as 8 years or as old as 16 or 17. They usually start about a year after your breasts have started to develop. Whenever you start, remember that this is the time that it 'normal' for your body.

How often do periods happen?

Most girls have periods roughly every 28 to 30 days and they last a few days. But when you first start having periods, they may come less often. About one in ten women will always have rather irregular periods.

How long do periods normally last?

Most periods last four or five days, but it is normal for periods to last two, three or four days or as long as six or seven days. The length of a girl’s period may change from month to month.

How do you know when you are going to have your first period?

Puberty usually starts with your breasts growing, along with hair growing under your arms and around the lips of your vagina – at the front. Some girls start to get a bit of discharge on their pants which shows that your hormones are beginning to rev up, and it is likely that your periods may start soon.

How do you know that your period is about to start?

An ache in the lower part of your tummy, tender breasts or any of the things that happen with PMT can alert you to the fact that your period is on its way. But for some girls– bleeding is the first sign, and if so, keeping some tampons or sanitary towels in a handy place will make you feel less worried about being caught unawares. Keeping a diary will also help you know roughly when you are due and how regular you are.

Are periods painful?

Almost half of all women say that they get some pain with their period. Some women get stomach, back or kidney cramps during their periods (the medical name is dysmenorrhoea - what a long word, but sounds serious, doesn't it?!). But there’s no need to suffer, as the pain is usually helped by paracetamol or ibuprofen (remember to check on the packet for the correct dose for your age). If this doesn’t help you can see your doctor who can prescribe special ‘stronger’ tablets. Taking exercise often helps period pains, as does a hot water bottle.

What is premenstrual tension (PMT)?

Nine out ten girls notice some mood and body changes for a day or two before the start of their period. These include: tender breasts, tiredness, grumpiness, more acne than usual, feeling bloated, feeling fed up. These premenstrual tension feelings go once your period starts.

Do women have periods for ever?

Most women stop having periods when they are about 50. This called the menopause.

Why do people stop having periods before they get old?

The most common reason is pregnancy.
Other common reasons in teenage girls include:

• losing weight (because of anorexia or other eating problems)
• taking lots of exercise (like running a marathon)
• lots of travel
• other reasons which are not clear