1, First of all, congratulations on your pregnancy 2, Thyroid surgery and post-surgery medications (Euthyrox/retinoids) do not affect pregnancy and are safe throughout pregnancy. 3. During the 1st-6th month of pregnancy, thyroid function is rechecked every month (six times in total), during which the dose of thyroxine tablets will be gradually increased. 4. From 6 to 10 months of pregnancy, thyroid function is rechecked only once (one time in total). 5. 6 weeks after delivery, thyroid function is rechecked once more. After that, the thyroxine tablets will return to normal. The above tests can be done in the hospital where the delivery takes place. Thyroid function includes (FT3, FT4, TSH) 6. Breast milk contains a very minute amount of thyroxine, which can be used for normal breastfeeding. 7.Thyroid tumor is the result of a combination of factors and will not be passed on to the child. 8. Contact us if you have any more questions.