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Everyone knows that pregnancy causes mood swings, but did you know that the hormone surge you experience during pregnancy can affect how your thyroid functions?

Hyperthyroidism and hypothyroidism are conditions with a pronounced effect on pregnancy and need to be handled with care. If you have either of these conditions, you will require regular testing and, often times, medication throughout your pregnancy.

What is hyperthyroidism during pregnancy?
Hyperthyroidism is a condition that develops when the thyroid gland makes too much thyroid hormone. During pregnancy, your body makes the hormone HCG (human chorionic gonadotropin). HCG is the hormone that pregnancy tests detect. It has mild thyroid stimulating effects and, as a result, can cause some symptoms of hyperthyroidism. In fact, HCG is partly responsible for the nausea you may experience during the first trimester. Hyperthyroidism with no apparent symptoms occurs in 10-20% of normal pregnant women during this period, and these women typically do not require treatment. The most common cause of Hyperthyroidism during pregnancy is Graves’ disease.

What are the signs and symptoms?
Often times, the signs and symptoms of hyperthyroidism start slowly, and you may not notice any changes at all. But if you think you’re at risk, pay close attention to any of the following:

  • Bulging eyes
  • Weight loss without trying
  • Increased appetite
  • Fast heart rate and fast breathing, even at rest
  • Increased sweating, and heat intolerance
  • Painful lump in your neck
  • Fatigue and difficulty sleeping
  • Tremors and muscle weakness
  • Diarrhea or constipation
  • Nervousness, tension and restlessness
  • Increased blood pressure, with headache, nausea, and blurred vision

What causes hyperthyroidism?

Autoimmune diseases
A problem with the immune system may make your thyroid gland produce too much thyroid hormone. For example, Graves’ disease is an autoimmune disease that increases thyroid hormone.

Family history
If a family member has thyroid disease or an autoimmune disease, your risk for thyroid issues is higher.

Certain medicines can cause hyperthyroidism. Ask your doctor if any of the medications you are taking can cause hyperthyroidism.

Infection near the thyroid gland may damage the gland.

Thyroid problems
An enlarged or swollen thyroid, lumps caused by infections, or thyroid cancer can affect how your thyroid is functioning.

High iodine levels
The thyroid gland uses iodine to create thyroid hormone. The thyroid can produce too much thyroid hormone if your iodine levels are high.

How does hyperthyroidism affect the mother and baby?
Uncontrolled hyperthyroidism during pregnancy can lead to:

  • Congestive heart failure
  • Preeclampsia, a dangerous rise in blood pressure in late pregnancy
  • Thyroid storm, a sudden, severe worsening of symptoms
  • Miscarriage
  • Premature birth
  • Low birth weight

How is hyperthyroidism during pregnancy diagnosed?
If you’re experiencing any of the symptoms, alert your doctor. Make sure they are aware of your medical and family history, as well as what medicines you are currently taking. They will probably take a sample of your blood to check your thyroid hormone level.

When should I contact my doctor?

  • Your baby is moving less.
  • You have a fever.
  • You feel nervous and restless.
  • You have chills, a cough, or feel weak and achy.
  • You run out of thyroid medicine or have stopped taking it.
  • You have questions or concerns about your condition or care.


Information provided is for general background purposes and is not intended as a substitute for medical diagnosis or treatment by a trained professional. You should always consult your physician about any healthcare questions you may have, especially before trying a new medication, diet, fitness program, or approach to healthcare issues.
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