Perimenopause can begin eight to 10 years before menopause, when the ovaries gradually produce less oestrogen.
The condition is known to occur for women in their 40s but there are cases of it beginning for some woman in their 30s.
Perimenopause lasts up until menopause, the point when the ovaries stop releasing eggs.
In the last one to two years of perimenopause, the drop in oestrogen accelerates, said the Cleveland Clinic.
The health site added: “At this stage, many women may experience menopause symptoms.
“Women are still having menstrual cycles during this time and can get pregnant.”
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