by email@example.com (322 Posts), Mon Aug 28, 2006 03:16 pm
Hyperthyroidism is a substantial risk factor for preeclampsia. (It is also a risk for spontaneous preterm labor). This is particularly true when it is not controlled. Thyroid hormone circulates as T3 and T4. T3 is the active hormone, and a ÃƒÅ¸-blocker blocks the conversion from T3 to T4. The ÃƒÅ¸-blocker also blocks the effects of hyperthyroidism. To decrease the production of T4, a drug such as PTU (propylthiouracil) is frequently prescribed. Sometimes radioactive iodine is used to treat the thyroid. PTU can be used in pregnancy. Radioactive iodine cannot be used in pregnancy. Hyperthyroidism should always be definitively treated before pregnancy.
Hyperthyroidism is one of the most treatable conditions where treatment has a very positive impact on pregnancy outcome.
Hypothyroidism is also a risk for preeclampsia. The magnitude of risk is not as great as for hyperthyroidism. Many women with hypothyroidism were previously hyperthyroid due to autoimmune thyroiditis. At first the inflammation associated with the autoimmmunity stimulates the glad to release thyroid hormone. Over time, it destroys the thyroid so that replacement is needed.
Hypothyroidism should be aggressively treated in pregnancy. There is some indication that a small reduction in thyroid hormone can affect brain development.