The walls of your womb are made of muscle. When your period is due, your body releases hormone-like substances called prostaglandins which make the muscle of your womb contract. This is what causes the pain you feel during your period. The muscle contracts so the lining of your womb (endometrium) can come out through your vagina – that’s the blood, with some other bits and pieces.
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There are 2 types of painful periods; pain without a known cause and pain with a known cause.
Pain without an underlying problem (primary dysmenorrhoea)
This is common and affects more than half of all women at some stage. For many people it starts within a year of your first period. It often gets better as you get older or after you have a baby.
Pain with a known cause (secondary dysmenorrhoea)
This is when you have painful periods because you have another, underlying condition. Tip offs that this could be happening are:
- if you get period pain for the first time when you're over 25 years of age
- if your period pain lasts the whole way through your period
- if your period pain gets worse and worse each time.
The most common cause of secondary dysmenorrhoea is endometriosis (where tissue that is similar to your womb lining grows outside the womb).
Other causes include:
- fibroids (non-cancerous growths in or around your womb)
- pelvic inflammatory disease (an infection of the womb, fallopian tubes and ovaries)
- adenomyosis (abnormal tissue growth in the womb wall)
- copper intrauterine devices (IUDs) used for contraception
- ovarian cysts.
If you think you might have secondary dysmenorrhoea, see your healthcare provider. They will ask you about your pain and may examine your tummy. You may be referred to a specialist (gynaecologist) who may carry out further investigations, eg, a blood test, ultrasound scan of your womb and pelvis, or a hysteroscopy (procedure to look inside your uterus).