I think it possibly could or could affect the dosage you need. It would probably be a good idea to go in and get your thyroid checked again to be sure you're on the right dosage. My husband has Hashimotos and I know the dosage he needs to take constantly fluctuates over time, and I believe stress plays a big role in it. Being off the pill could change the amount of stress you're under, so if you have a similar thyroid condition, it wouldn't hurt to get your numbers re-checked. I believe I read somewhere that being on BCPs could affect your thyroid numbers too.