I respectfully beg to differ--it is NOT a well-known fact that birth control should not be taken while breastfeeding. This may be known by some health professionals but I assure you that there is information everywhere a lay-person will look which leads countless women to believe that Mirena is safe to use while breastfeeding. In fact it's hard to find information for a patient which tells them that it is NOT safe or at the very least, questionable, to breastfeed while using Mirena!
Even La Leche League--the "Breastfeeding Nazis"--support the use of progestin-only contraception while breastfeeding.
ALL of my practitioners, including my midwife, OB, primary care physician, knew that I was breastfeeding, and I was ASSURED that it was a safe option for a breastfeeding mom.
I'm glad for you that you were given this information, but many, many women have been told the exact opposite by their doctors.