Thyroxine is very safe for pregnancy. You may even need to increase the dose during pregnancy.
But you must check during pregnancy, otherwise if you have hypothyroidism during early pregnancy, the baby may have lower IQ in the future according to one study published in New England Journal of Medicine 1999.
In HK, they do not routinely check the thyroid function during pregnancy. You may go to private to check during each trimester if you are worried.
Oh, kitty1, sorry that I mistaken you have hypothyroid(too little) and on thyroxine replacement. I think you mean you are hyperthyroid (too much) and on ANTI-thyroid drug.
Hyperthyroid has a lot of problem during pregnancy, there is antithyroid drug safe for pregnancy and all you need is to close monitor during prenancy la. If you not take the medicine and have hyperthyroidism , there will be lots of risk for you and baby.
Different tablet dosages have different colors, all depends on how severe your problem is. You don't need to care about what color other ppl are taking la.