Causes of dysmenorrhoea

Primary dysmenorrhoea with no underlying cause is believed to be due to an increase or imbalance in the amount of prostaglandins released by the lining of the uterus (endometrium) during menstruation⁷. Prostaglandin release is triggered by a drop in the amount of progesterone during the normal menstrual cycle¹².

This release of prostaglandins prompts:

• Uterine contractions 
• Reduced blood flow
• Uterine hypoxia (lack of oxygen)
• Hypersensitisation of the peripheral nerves^7,13.

Uterine hypoxia is the cause of the cramping pains in primary dysmenorrhoea¹³. Further, the tissue breakdown that happens during menstruation causes elevated prostaglandin levels¹².

Secondary dysmenorrhoea is caused by underlying gynaecological pathologies, such as¹:

• Adenomyosis
• Endometriosis
• Endometrial polyps
• Fibroids
• Gynaecological cancers
• Pelvic inflammatory disease.

It can also arise because of intrauterine device (IUD) insertion¹.

What are the risk factors for dysmenorrhoea? 

There are several different factors that can either increase or decrease the risk of dysmenorrhoea or cause increased pain severity^1,9.

Dysmenorrhoea risk factors^1,9

Increased risk of dysmenorrhoea^1,9

Starting periods at a younger age	Have not given birth	Stress	Heavy menstrual bleeding	Family history of dysmenorrhoea

Decreased risk of dysmenorrhoea⁹

Older age (improves in the third decade)14	Have given birth	High fruit and vegetable intake	Oral hormonal contraception