Menopause, sometimes mistaken as a disease or disorder, is a natural part of ageing defined as a decline in a woman's reproductive hormones. It usually occurs in the 40s-50s and marks the end of menstrual cycles. It follows three stages: Perimenopause (estrogen levels decline), Menopause (ovaries stop releasing egg cells), and Post-menopause (time of 12 consecutive months without menstruation).