Krisha McCoy, MS
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:
Hashimoto’s disease is the most common cause of
hypothyroidism. The immune system attacks the thyroid gland. Other causes of hypothyroidism in pregnancy include:
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.
Risk factors that increase your chances of developing a thyroid disorder include:
If you have any of these symptoms, do not assume it is due to a thyroid disorder. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. You may be referred to a doctor who specializes in hormone disorders (endocrinologist).
Your doctor may need to test your body fluids. This can be done with blood tests.
Your doctor may need to scan your thyroid to determine whether it is overactive. This can be done with a radioactive scan of the thyroid.
Untreated hypothyroidism in pregnancy can:
To treat hypothyroidism, your doctor will prescribe an oral medicine.
can replace the hormone your thyroid is not producing.
Untreated hyperthyroidism in pregnancy is associated with:
Mild hyperthyroidism during pregnancy is often monitored closely without therapy. In some cases, you may need to take medicine. If antithyroid medicines do not work,
of your thyroid gland may be done. It is rarely recommended during pregnancy. Treatment with radioiodine destroys the thyroid gland. It is not done during pregnancy because of risk to the fetus.
Hormones associated with pregnancy can cause changes in thyroid hormone levels. Therefore, your medicine needs may vary during pregnancy. Your doctor will likely check your blood levels of thyroid hormone every 6-8 weeks during pregnancy and four weeks after your medicine dose is changed.
There are no known guidelines to prevent thyroid disorders in pregnancy. If you think you are at risk for this disorder, talk to your doctor.
The American Congress of Obstetricians and Gynecologists
American Thyroid Association
The Society of Obstetricians and Gynaecologists of Canada
Thyroid Foundation of Canada
American College of Obstetricians and Gynecologists. Thyroid disease in pregnancy.
Practice Bulletin No. 37.
August 2002 (reaffirmed 2010).
Graves’ disease. American Thyroid Association website. Available at:
http://www.thyroid.org/patients/brochures/Graves_brochure.pdf. Published 2012. Accessed December 18, 2012.
Hashimoto’s disease: what it is and how it’s treated. American Academy of Family Physicians website. Available at:
http://familydoctor.org/548.xml. Updated November 2010. Accessed December 18, 2012.
Torpy J, Lynm C, Glass R. Hyperthyroidism.
JAMA. 2005;294(1):146. Available at:
http://jama.ama-assn.org/cgi/content/full/294/1/146. Accessed December 18, 2012.
Last reviewed November 2012 by Andrea Chisholm
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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