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What are menopause and perimenopause?

  • Perimenopause happens when your periods become irregular and menopause is when your periods stop altogether.
  • Menopause is caused by a fall in hormone levels and usually affects women between the ages of 45 and 55, but it can happen earlier.
  • Menopause and perimenopause can affect anyone who has periods.
  • Menopause itself is defined as not having a period for 12 months and you're not using hormonal contraception.
  • Common symptoms include hot flushes, low mood, sleep problems and memory problems.
  • There's no routine test for perimenopause and menopause. A doctor may diagnose it based on your age and symptoms
  • Early menopause or premature ovarian insufficiency can happen before the age of 45. It can be caused by surgery to remove the ovaries (oophorectomy). Sometimes the reason is unknown.

Page last reviewed: 19 May 2026
Next review due: 19 May 2029