Is the newly detected hyperthyroidism after pregnancy a true hyperthyroidism? Since the placenta secretes chorionic gonadotropin (β-HCG) after pregnancy, this hormone has a weak thyroid stimulating effect, therefore, a considerable number of women can have slight hyperthyroidism changes when their thyroid function is tested around the third month of pregnancy, this condition is called hyperthyroidism in pregnancy syndrome, it is physiological and current research believes that it will not have adverse effects on the fetus and the mother. It is a physiological condition that is not considered to have adverse effects on the fetus or the mother, and can return to normal on its own as pregnancy progresses, so there is no need to treat it. However, pregnancy is often accompanied by hyperthyroidism-like symptoms such as palpitations, fatigue, nausea and vomiting, making it difficult to distinguish from true hyperthyroidism. In this case, providing a detailed medical history will help your doctor to identify it, especially if there is any previous history of hyperthyroidism and the results of thyroid hormone receptor antibody tests. What medications should be used for hyperthyroidism during pregnancy If the diagnosis of hyperthyroidism Graves’ disease (the most common form of hyperthyroidism) is confirmed, the choice of medication is very important, regardless of whether it is a previous diagnosis or a new finding: propylthiouracil is preferred from the beginning of pregnancy to the first trimester; methimazole is preferred from the second six months of pregnancy to breastfeeding. Are these drugs safe and do they have side effects for the mother and child There is no such thing as an anti-thyroid drug that is absolutely safe and free of side effects, but the so-called side effects are not a certainty but a small probability of occurrence. The risk of adverse effects to the fetus from methimazole is mainly in the first trimester, which may cause dysplasia of the skin of the head, nostrils and esophagus, and is less pronounced after three months, while this aspect of propylthiouracil is relatively safe and therefore propylthiouracil is preferred in the first trimester. However, the risk of liver damage to the mother is slightly higher with propylthiouracil than with methimazole, and very few people can have more pronounced liver damage, so methimazole is recommended for the second six months. The same is recommended for breastfeeding, and it is recommended to take the drug after breastfeeding. After a diagnosis of hyperthyroidism Graves’ disease, the benefits of drug treatment far outweigh the risks, both for the fetus and the mother, and must be treated decisively. How often should hyperthyroidism be reviewed during pregnancy? Generally, thyroid function should be reviewed once in 2-6 weeks, and blood and liver function should be monitored as appropriate.