Hi, I Got The Mirena IUD Removed Yesterday After Having

Hi, I got the mirena IUD removed yesterday after having it for 3 years 10 months. i had no problems on the mirena. I didnt have periods and no cramping... no scary stories that are mentioned everywhere. I got it removed because i want to begin TTC (trying to conceive). When she removed it she said that all my female organs looked great and healthy and have no female medical condition. She recommended using prenatal to help the TTC process.. Will this help better my chances of conception? Also one more thing, i have a hypothyroidism disease, is it safe to take prenatal vitamins with synthroid?