Why Am I Experiencing Irregular Periods With PCOD Despite Exercising Regularly?

Hi Doctor, Iam suffering from pcod since 3 years. It started after my marriage. I was 68kgs at that time. And started gaining weight more.Doctor adviced to reduce weight. Trying alot to reduce weight but is it not happening...now my weight is 72. I have observed 1 thing, when iam doing workouts every day, iam not loosing weight but iam seeing inch loss. There no change in my weight even now. The question is why is this irregular periods happening for almost every women in these days why not my mother nd grand mother did not face these problem during those days. Can u please help to understand how can I regulate my periods.. Thank you