Hypothyroidism has different causes. For general hypothyroidism, lifelong medication is advocated because general hypothyroidism is caused by a lack of thyroid hormones and requires adequate thyroid hormone supplementation to restore its thyroid function. Patients who do not need lifelong medication often present clinically with subthyroiditis, which is a condition in which the thyroid gland becomes hyperactive in the early stages and hypothyroid in the later stages, but generally subthyroiditis can recover on its own and does not require thyroid hormone supplementation. However, very few people will experience hypothyroidism for a longer period of time and will require appropriate amounts of thyroid hormone supplementation. Patients with hypothyroidism in combination with pregnancy or subclinical hypothyroidism will require thyroid hormone supplementation for a short period of time to improve their thyroid function. For patients with general hypothyroidism, lifelong thyroid hormone therapy is required to maintain normal thyroid function.