Breastfeeding after taking hyperthyroid medicines

[RS54]

Hi,
I am Hyperthyroid and on Methimazole 5mg once daily. I have 2 weeks old baby and my doctor suggested me not to breastfeed my baby for 3hrs after taking methimez. I had to give her formula during this 3 hrs as i couldnot use pump well. Due to formula milk she is suffering with constipation. Please help is it ok to brestfeed after taking methimez.

Also could you please suggest if there are any ways to improve the milk supply.

Thanks in Advance

[admin]

RS54,

Methimazole is rated an L2- limited data-probably compatible. The amount passed into breast milk is only 2.3% of your dose. Even at doses of 20 mg/day, no changes in infant TSH, T4 or T3 were noted in over 12 months of study. The dose you are on is very small, the medication is most concentrated in the first hour after taking the medication so we recommend taking the medication right after breastfeeding so you have at least 2 hour break before feeding again. Monitor your infant for signs of hypothyroidism, and their thyroid functions to be on safe side.


Sandra Lovato R.N.
InfantRisk Center
806-352-2519