Hyperthyroidism does have an impact on pregnancy, including an increased chance of spontaneous miscarriage, preterm birth and low birth weight, and in severe cases, pre-eclampsia and congestive heart failure, as well as an increased chance of neonatal abnormalities, but with proper control before and during pregnancy, a healthy child can still be born. ”I thought taking medication during pregnancy would affect the baby?” It is true that antithyroid medications have been reported to cause abnormal fetal development, but the probability of this is very low, with only a few cases reported, and in fact many pregnant women are treated with antithyroid medications each year, so one cannot advise a hyperthyroid patient not to become pregnant just because of these reports. However, most patients who take medication to achieve normal thyroid function and maintain treatment for a period of time will not relapse immediately even if they stop taking medication, and many patients may be in remission for more than six months. In this way, it is not necessary to wait until hyperthyroidism is in complete remission and completely cured before getting pregnant. If you are not too old, your goiter is not obvious, your thyroid gland is negative for stimulating antibodies, and the probability of a short term relapse after stopping the medication for hyperthyroidism control is estimated to be small, you can wait until you are cured before getting pregnant. If you are older, have an obvious enlarged thyroid gland and positive thyroid stimulating antibodies, you should not wait until you have a greater chance of relapse after stopping the medication. Pregnancy is the most common allogeneic transplant in nature. The mother’s and fetus’ blood types are different but can not be rejected, and the mother’s immune system is bound to change a lot to adapt to it. What should I pay attention to when taking medication during pregnancy? It is important to be aware of the effects of thyroid function on the fetus during pregnancy as opposed to medication, so it is important to monitor changes in thyroid function during pregnancy to keep thyroid function at a slightly higher than normal level. This is because, on the one hand, pregnancy itself affects the results of thyroid function tests and, on the other hand, if the mother’s thyroid function is low, it has an effect on the child’s neurological development. Recent data show that even mild hypothyroidism in the mother can affect the child’s mental development, compared to mild hyperthyroidism, so it is better to keep the thyroid function at a normal high level for insurance purposes.