Thyroid Disorders in Pregnancy
Definition
The thyroid is a butterfly-shaped gland in the front of the neck. Pregnancy hormones can cause changes to thyroid hormone levels. This can raise the risk of pregnancy problems when it is not treated. There are two types of problems:
- Hypothyroidism —the thyroid gland does not make enough thyroid hormone
- Hyperthyroidism —the thyroid gland makes too much thyroid hormone
The Thyroid GlandCopyright © Nucleus Medical Media, Inc. |
Causes TOP
Hypothyroidism in pregnancy may be caused by:
- An immune system problem known as Hashimoto disease, the most common cause
- Not enough treatment for pre-existing hypothyroidism
- Over treating hyperthyroidism
Hyperthyroidism in pregnancy may be caused by:
- Overactivity of the thyroid gland known as Graves disease, the most common cause
- Very high levels of human chorionic gonadotropin (hCG)
Risk Factors TOP
Things that may raise the risk of this problem are:
- A personal or family history of a thyroid problem
- Having been treated for a thyroid problem
- An enlarged thyroid gland (goiter)
- Hyperemesis gravidarum, a severe form of morning sickness
- A personal or family history of problems with the immune system
Symptoms TOP
Hypothyroidism problems are:
- Tiredness
- Dry skin
- Constipation
- Weight gain
- Slow heartbeat
- Memory problems
- Depression
Hyperthyroidism problems are:
- Losing weight without trying
- Sweating
- Shaking
- Nervousness
- Diarrhea
- Problems sleeping
- Bulging eyes
- Fast or abnormal heart rhythm
Diagnosis TOP
The doctor will ask about your symptoms and health history. A physical exam will be done.
Your thyroid hormone levels will be tested. Other blood tests may also be done.
Images may be taken of the thyroid.
Treatment TOP
Hypothyroidism
Medicine will be given to replace the hormone. Thyroid levels will be checked often and the dose may need to be changed.
Hyperthyroidism
Mild hyperthyroidism will be watched closely. Some people may need to take medicine. Your medicine needs may change during pregnancy. Your doctor will check your thyroid hormone levels every 6 to 8 weeks during pregnancy and 4 weeks after a change in dose.
If medicine does not work, the thyroid gland may need to be removed. Radioiodine is used to destroy the thyroid gland. It is rarely done during pregnancy because of the risk to the fetus.
Prevention TOP
There are no known methods to prevent this health problem. Proper prenatal care can help to find problems before they happen.
RESOURCES:
The American Congress of Obstetricians and Gynecologists
http://www.acog.org
American Thyroid Association
http://www.thyroid.org
CANADIAN RESOURCES:
The Society of Obstetricians and Gynaecologists of Canada
https://sogc.org
Thyroid Foundation of Canada
http://www.thyroid.ca
REFERENCES:
American College of Obstetricians and Gynecologists. Practice Bulletin No. 148: Thyroid disease in pregnancy. Obstet Gynecol. 2015;125(4):996-1005.
Graves disease in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/graves-disease-in-adults. Accessed August 24, 2021.
Hashimoto’s disease. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/condition/hashimotos-disease. Accessed August 24, 2021.
Pregnancy & thyroid disease. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/endocrine-diseases/pregnancy-thyroid-disease. Accessed August 24, 2021.
Smith TJ, Hegedüs L. Graves' Disease. N Engl J Med. 2016 Oct 20;375(16):1552-1565, commentaries can be found in N Engl J Med 2017 Jan 12;376(2):184, N Engl J Med 2017 Jan 12;376(2):185.
Last reviewed July 2021 by
EBSCO Medical Review BoardBeverly Siegal, MD, FACOG
Last Updated: 8/24/2021