The purpose of woman's period is, it indicates her fertility
. In some communities in India when a girl attains menarche
, celebrations are done because menarche means now the girl is fertile. Regular cycles indicate that ovary is working well and releasing egg monthly. Not only fertility, the female hormones produced by ovaries in each cycle are necesarry for total body well being of woman. Estrogen
hormone has effect on heart, bone etc. You must have heard about the changes that occur in the body when a woman attains menopause
. So you can imagine the importance of cycles.