Periods (Menstruation)

A period is a normal part of the menstrual cycle in women. It occurs about 2 weeks after ovulation, if an egg isn’t fertilised.

During ovulation, the lining of the womb thickens in preparation for the arrival of a fertilised egg. If the egg isn’t fertilised within 24 hours of ovulation, this lining detaches itself and is passed out of the body in the form of a period.

It occurs once a month, but the exact length of time between periods differs between women. Menstruation itself usually lasts around five days, with the heaviest flow occurring in the first 48 hours.

Women experience their first period during puberty, usually around the age of 12. However, it can occur earlier or later and this is nothing to worry about.

Premenstrual tension

Some women experience a range of physical and psychological symptoms in the days immediately before their period. This is known as premenstrual syndrome (PMS) and is caused by hormonal changes in the body.

Common symptoms of PMS include:

Sanitary products

There are many sanitary products available to absorb or stem the flow of blood during your period. You should choose whichever one you are most comfortable with.

Commonly-used products include:


These are inserted into the vagina and absorb all the menstruation. When used correctly, you won’t notice them or feel uncomfortable. They have a string at the end which allows you easily remove the tampon when you need to.

It’s important not to leave a tampon in for longer than eight hours at a time, as this can lead to a serious, potentially life-threatening condition known as toxic shock syndrome.

Sanitary pads

These are attached to your underwear with adhesive strips so that they catch and absorb the menstruation. There are different sizes available to cater for both light and heavy menstrual flow.

Menstrual cups

These are placed within the vagina and collect the menstruation. Unlike sanitary pads and tampons, menstrual cups can be washed and used again.

If you notice any changes in your menstrual cycle, it’s important to tell a doctor about it. Common problems include:

Bleeding between periods

This can be caused by:

  • Starting a new type of hormonal contraception, such as the pill, patch or injection
  • A problem with your contraception
  • Taking emergency contraception
  • Vaginal injury
  • Sexually transmitted infections (STIs)
  • Changes in the cervix or lining of the womb

Painful periods

Some discomfort during menstruation is normal. You may experience a dull or sharp pain in your stomach, back and thighs. However, if you’re experiencing more pain than normal during your period, it could be a sign of:

  • Endometriosis
  • Non-cancerous growths in the womb
  • Pelvic inflammatory disease (PID)

Bleeding after sex

This can be caused by:

  • Sexually transmitted infections (STIs)
  • Pelvic inflammatory disease (PID)
  • Vaginal dryness (this may be more common after the menopause)
  • Abnormalities of the cervix

Postmenopausal bleeding

This can be caused by:

  • Lower oestrogen levels resulting in vaginal thinning
  • Non-cancerous growths in the womb
  • A thickening of the womb lining
  • In rare cases, it can be a sign of cancer

Heavy periods

Also known as menorrhagia, if your period is heavier than normal it could have been caused by:

  • Infections
  • Cervical problems
  • Cancer (but this is rare)
  • Changes in the lining of the womb
  • Non cancerous growth in the womb
  • Changes in your hormones

What happens if you miss a period?

A missed period (amenorrhoea) could mean you’re pregnant, so you may want to take a pregnancy test. If these tests come back negative, tell a doctor if you miss more than three periods.

If you’re not looking to get pregnant, take a look at some of the contraception options available.

In some cases, missed periods can also be caused by a change in your lifestyle factors, such as your diet or the amount of exercise you do. Being underweight can also stop your periods.

The menopause

Women experience the menopause when ovulation stops, usually around your late 40s and early 50s. It’s a natural part of life, and it’s normal for menstruation to stop either gradually or suddenly.

It occurs because when ovulation stops, there’s no need for the womb lining to thicken as there’s no egg to be fertilised.

Women's Health