There are many drugs that interact with the birth control pill and you should discuss the use of any prescriptions with your doctor should you need them. Folic acid is a nutrient and does not interfere with the pill. However, you may want to look at getting the more active form of folate, as it is more effective for your goal of enhancing your immune system. I would recommend Folapro in this case, at no less than 400u a day, which is safe to use while on contraception.