Thyroid Disorders in Pregnancy



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

Things that may raise the risk of thyroid disorders 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



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


The doctor will ask about symptoms and health history. A physical exam will be done.

Thyroid hormone levels will be tested. Other blood tests may also be done.

Pictures may be taken of the thyroid.




Medicine will be given to replace the hormone. Thyroid levels will be checked often and the dose may need to be changed.


Mild hyperthyroidism will be watched closely. Some people may need to take medicine. The dose may need to change during pregnancy. Thyroid hormone levels will be checked 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 it. This is rarely done during pregnancy because of the risk to the fetus.


There are no known methods to prevent thyroid disorders in pregnancy. Proper prenatal care can help to find problems before they happen.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.