Breastfeeding and thyroid disease

So if you have a thyroid disorder it’s important that your thyroid hormone levels are well controlled after pregnancy, as well as before and during pregnancy.

Breastfeeding is safe while taking levothyroxine to treat an underactive thyroid (hypothyroidism) as it is secreted in extremely low levels into breastmilk.

It is generally safe to breastfeed while taking antithyroid drugs to treat an overactive thyroid (hyperthyroidism) provided the dose is low but you should check with your endocrinologist.

Antithyroid drugs are best taken in smaller doses over two or three times a day following a feed.

If you require higher doses of antithyroid drugs to control hyperthyroidism then your baby can have a blood test to check whether its thyroid is being affected.