Suggest Natural Remedy For Irregular Menses

Hi, I am 26+.My period is irregular so doctor prescribed me diane35 & told to continue till I plan to get pregnant. My period cycle became dependent on this. Now I am planning for a baby & I have PCO. I have not started trying yet but I want my period cycle to be regular before I plan for baby. My period is either prolong or delay 2-3 months without medicine. Please advise how my period can be regular without taking any medicine.