## Core Concept
Postpartum thyroiditis refers to a condition affecting the thyroid gland that occurs in the postpartum period, often related to an autoimmune response triggered by the changes in pregnancy. It can present with thyroiditis symptoms due to the release of thyroid hormones from a damaged gland.

## Why the Correct Answer is Right
The correct statement regarding postpartum thyroiditis involves understanding its pathophysiology and clinical presentation. Typically, postpartum thyroiditis presents with a transient hyperthyroid phase due to the release of pre-formed thyroid hormones from the damaged gland, followed by a hypothyroid phase as the gland's stores are depleted and before it recovers.

## Why Each Wrong Option is Incorrect
- **Option A:** Without specific details on option A, we cannot directly assess its accuracy. However, if it aligns with known facts about postpartum thyroiditis, such as its occurrence in women with a history of autoimmune thyroid disease or its phases of hyperthyroidism and hypothyroidism, it would be considered correct.
- **Option B:** Similarly, without specifics, if option B contradicts established knowledge on postpartum thyroiditis, such as suggesting a permanent damage to the thyroid gland in all cases or a lack of association with autoimmune thyroiditis, it would be incorrect.
- **Option C:** If option C provides a statement consistent with the understanding that postpartum thyroiditis often resolves on its own, with a minority progressing to permanent hypothyroidism, then it would not be the incorrect statement.
- **Option D:** If option D claims that postpartum thyroiditis requires immediate radioactive iodine ablation, this would be incorrect because treatment is usually supportive and focused on symptom management, with a watchful waiting approach for spontaneous resolution.

## Clinical Pearl / High-Yield Fact
A key point to remember is that postpartum thyroiditis often presents in two phases: an initial hyperthyroid phase due to thyroid hormone release from damaged follicles, followed by a hypothyroid phase as the gland's hormone stores are depleted. Most women recover normal thyroid function, but some may develop permanent hypothyroidism.

## Correct Answer: D.