Can i breastfee my 7 days old baby if i have hyperthyroidism?

Generally yes: You can breastfeed unless you get a dose of radioiodine. Breastfeeding while taking antithyroid drugs (such as methimazole) haven't been studied that well, but is thought to be safe. Make sure you get adequate nutrition since hyperthyroidism and breastfeeding will both drain calories. The amount of breast milk you produce can also be affected.