I'm not trying to bash drs here but I honestly wonder sometimes where they get their info! Anyting you read will tell you that babies get all their iron needed when breastfeeding exclusively for the first 6 mos. Even for the first yr they are fine but esp the first 6 mos.
Unless your baby had a specific medical issue you do not need to supplement them with any vitamins if you are exclusively bfing.
My 14 mos old is still 90% bf and our ped even said that he's getting all that he needs until 18 mos-and after that it just depends on individual kids.
I don't have specific link but I think www.kellymom.com ?? has more info or www.lalecheleague.org will for sure
Good luck
Ann, Full-time mama of 2 crazy kids and a sling'n toddler