I was just wondering why does menopause occur in women?

Menopause: defined as no cycle for one year, because ovaries stop producing eggs and female hormone

Loss of estrogen: Menopause occurs when your ovaries stop functioning in terms of making eggs and estrogen. Mother nature, in her wisdom, has decided that older women should not be reproducing, since they may die before their offspring can be self sufficient. This was especially true many years ago when the average life expectancy was only to age 40.