A 28-year-old woman presents with palpitations, weight loss, heat intolerance, and a diffuse goitre. TSH is <0.01 mIU/L and free T4 is markedly elevated. Thyroid uptake scan shows diffusely elevated uptake. She is in the first trimester of pregnancy. The SAFEST initial management is:

• A Radioiodine ablation
• B Methimazole
• C Thyroidectomy in first trimester
• D Propylthiouracil (PTU) at the lowest effective dose ✓

Explanation

In pregnancy, both methimazole (MMI) and propylthiouracil (PTU) are used. In the first trimester, PTU is preferred because methimazole is associated with aplasia cutis and methimazole embryopathy (choanal atresia, oesophageal atresia). After the first trimester, switching to methimazole reduces the risk of PTU-associated hepatotoxicity. Radioiodine is absolutely contraindicated in pregnancy. Thyroidectomy carries fetal risk and is reserved for those who cannot tolerate antithyroid drugs, preferably in the second trimester.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.