## **Core Concept**
Thyrotoxicosis during pregnancy requires careful management to ensure the health of both the mother and the fetus. The primary goal is to control symptoms while minimizing risks to the fetus. Treatment options include antithyroid medications, radioactive iodine (which is generally avoided in pregnancy), and surgery in select cases.

## **Why the Correct Answer is Right**
The correct answer, **Propylthiouracil (PTU)**, is often the preferred choice for treating hyperthyroidism during the first trimester of pregnancy. PTU is effective in controlling hyperthyroidism by inhibiting thyroid hormone synthesis. It is particularly favored early in pregnancy due to the lower risk of major congenital anomalies compared to methimazole, although both are used.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Radioactive iodine is contraindicated in pregnancy due to the risk of ablating the fetal thyroid gland, leading to hypothyroidism in the fetus.
- **Option B:** Methimazole is an alternative to PTU but is generally avoided in the first trimester due to a higher risk of congenital anomalies, such as esophageal atresia and choanal atresia.
- **Option D:** Surgery is usually reserved for cases where antithyroid drugs are not tolerated or contraindicated, or in the case of a large goiter or suspected thyroid cancer. It is not the first line of treatment.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **Propylthiouracil (PTU) is often preferred in the first trimester** of pregnancy for treating thyrotoxicosis due to its lower risk of congenital anomalies compared to methimazole. However, due to the risk of liver toxicity with PTU, it is sometimes switched to methimazole after the first trimester.

## **Correct Answer:** . Propylthiouracil (PTU)