How to tell my mom that contraceptive pills will make my periods regular?

Just tell her: just say... Mom, my periods are irregular and I want to be (or I am) on birth control pills to regulate my periods. Although, I don't understand why, at age 38 as your profile states, you would need to have this discussion.

Difficult to know: How you communicate with your mother a complex issue and difficult to coach from a distance. What is true is that the original research behind ocps was done to make periods more regular, diminish ovulation pain and or blood loss. The reduced birth rate was a side effect that eventually became its main selling point. Mayby the facts will help.