What causes period pain?

Period pain occurs when the muscular wall of the womb tightens (contracts). Mild contractions continually pass through your womb, but they're usually so mild that most women can't feel them.

During your period, the wall of the womb starts to contract more vigorously to encourage the womb lining to shed away as part of your monthly period.

When the muscular wall of the womb contracts, it compresses the blood vessels lining your womb. This temporarily cuts off the blood supply and hence oxygen supplyto your womb. Without oxygen, the tissues in your womb release chemicals that trigger pain.

While your body is releasing these pain-triggering chemicals, it's also producing other chemicals called prostaglandins. These encourage the womb muscles to contract more, further increasing the level of pain.

It's not known why some women experience more period pain than others. It may be that some women have a build-up of prostaglandins, which means they experience stronger contractions.

Period pain caused by a condition

Less commonly, period pain can be caused by an underlying medical condition. Doctors sometimes call this secondary dysmenorrhoea.

Period pain linked to an underlying condition tends to affect older women. Women aged 30 to 45 are most commonly affected.

Conditions that can cause period pain include:

  • endometriosis where cells that normally line the womb start to grow in other places, such as in the fallopian tubes and ovaries; these cells can cause intense pain when they shed and fall away
  • fibroids non-cancerous tumours that can grow in the womb and can make your periods heavy and painful
  • pelvic inflammatory disease where your womb, fallopian tubes and ovaries become infected with bacteria, causing them to become severely inflamed
  • adenomyosis where the tissue that normally lines the womb starts to grow within the muscular womb wall, making your periods particularly painful

An intrauterine device (IUD) is a type of contraception made from copper and plastic that fits inside the womb. It can also sometimes cause period pain, particularly during the first few months after it's inserted.

You may notice a change in your normal pattern of pain if your period pain is linked to one of the above conditions. For example, the pain may be more severe or it may last much longer than normal.

If your period pain is caused by an underlying condition, you may also experience:

  • irregular periods
  • bleeding in between periods
  • a thick or foul-smelling vaginal discharge
  • pain during sex

See your GP if you experience any of these symptoms.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 21 Dec 2018