Re: Levothyroxine & Breastfeeding
First... Congratulations on the new baby! You're in a lovely time of life, and I'm happy for you.
Just because your TSH is low doesn't mean you are overmedicated. My own TSH has been .02 for two years, and I'm not overmedicated or hyper. So... The biggest question is - How do you feel? Do you have signs like shakiness, fast bowels, insatiable appetite, extreme weight loss, etc? If you don't have any signs beyond the bit of nervousness that's normal for any new mother, you can't say you're overmedicated.
Then... even if you are taking slightly too much levoT, only a small fraction of it crosses into the breast milk. I found information from an article in Pediatrics magazine 2001;108:776-89, titled "The transfer of drugs and other chemicals into human milk". It says that the amount of thyroid hormone transferred into human milk is too low to affect blood thyroid hormone levels in newborns. The American Academy of Pediatrics considers levoT compatible with breastfeeding and has reported that no observable change is seen in nursing infants whose mothers are taking it.
If the baby is jumpy and restless, it could be just the way she's neurologically wired, or she could be sensing your own agitation and reacting to it.
I guess this doesn't really help you that much... But truthfully, neither does watching just your TSH. Unless you know your free thyroid hormone levels as well, you can't truly know if you're overmedicated or not. If the MD won't test your thyroid levels, you then have to fall back on your signs and symptoms instead, and that isn't very scientific.