The thyroid is a butterfly-shaped gland located in the front of the neck. It produces hormones that control metabolism. Pregnancy hormones can affect thyroid hormones. Untreated thyroid disorders in pregnancy increase the risk of pregnancy complications. It may cause harm to the developing fetus. There are two types of thyroid disorders:

  • Hypothyroidism —the thyroid gland does not produce enough thyroid hormone
  • Hyperthyroidism —the thyroid gland produces too much thyroid hormone

The Thyroid Gland
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Hashimotos disease is the most common cause of hypothyroidism. The immune system attacks the thyroid gland. Other causes of hypothyroidism in pregnancy include:

  • Inadequate treatment of pre-existing hypothyroidism
  • Overtreatment of hyperthyroidism

Graves disease is characterized by overactivity of the thyroid. It is the most common cause of hyperthyroidism. Another cause of hyperthyroidism in pregnancy is very high levels of human chorionic gonadotropin (hCG). However, cases of high hCG can resolve on their own.