Final answer:
Postpartum thyroiditis is caused by the infiltration of autoantibodies that attack thyroid-stimulating hormone receptors, leading to overstimulation of the thyroid. It typically follows an autoimmune mechanism and is related to thyroid disorders such as Hashimoto thyroiditis.
Step-by-step explanation:
Postpartum thyroiditis is characterized by inflammation of the thyroid gland after childbirth and is commonly autoimmune in nature. During this condition, the thyroid gland is infiltrated by autoantibodies that target thyroid-stimulating hormone (TSH) receptors, leading to an overstimulation of the thyroid. This autoimmune response may cause a transient period of hyperthyroidism followed by a hypothyroid phase, and eventually leading to a return to euthyroid state or permanent hypothyroidism in some cases.
Hashimoto thyroiditis is another form of thyroiditis, wherein the thyroid gland is attacked by cytotoxic lymphocytes, macrophages, and autoantibodies, leading to hypothyroidism over time. Postpartum thyroiditis may share some immunological features with Hashimoto's, but is distinguished by its timing after pregnancy and generally follows a different course.