Which medication is recommended for hyperthyroidism during the first trimester of pregnancy?

During the first trimester of pregnancy, Propylthiouracil (PTU) is the recommended medication for managing hyperthyroidism. The main reason for this recommendation is related to the safety profile of PTU compared to Methimazole, particularly in the early stages of pregnancy.

PTU is preferred because it has a lower risk of teratogenic effects during the critical period of fetal organogenesis, which happens predominantly during the first trimester. While Methimazole is effective for hyperthyroidism, it has been associated with congenital anomalies, especially when used in the early weeks of pregnancy. Therefore, to minimize risks to the developing fetus, PTU is usually the first-line treatment during this time.

In contrast, Levothyroxine is not used for hyperthyroidism; it is the replacement therapy for hypothyroidism. Atenolol, a beta-blocker, may be used to manage symptoms of hyperthyroidism (like tachycardia) but does not treat the underlying thyroid condition itself and also carries its own risks during pregnancy. Thus, PTU stands out as the most appropriate choice for managing hyperthyroidism in the first trimester.