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Thyroid Disease

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Thyroid Disease and Pregnancy

Thyroid disease occurs when the thyroid gland, located in the neck, produces too much or too little of the thyroid hormone. Thyroid hormones regulate our metabolism and many other important functions in the body.

Thyroid hormones can also impact a woman’s pregnancy and the development of the fetus. Women with thyroid disorders may face complex pregnancies with increased risks to the health and safety of mother and baby.

Types of Thyroid Disease

Common thyroid disorders in pregnancy include:

  • Hypothyroidism (underactive thyroid) – when the thyroid gland doesn’t produce enough thyroid hormones, causing metabolism to slow down; during pregnancy, a woman’s body requires additional thyroid hormones for herself and the developing fetus
  • Hyperthyroidism (overactive thyroid) – when the thyroid gland produces more thyroid hormones than the body needs, causing metabolism to speed up
  • Postpartum thyroiditis – inflammation of the thyroid after giving birth, which can raise hormone levels and lead to short-term hyperthyroidism followed by longer-term hypothyroidism

Plan Ahead to Improve Outcomes

If you have thyroid disease or a history of thyroid disease – including radioactive iodine or surgery treatments – it is best to talk with your health care provider before getting pregnant to improve outcomes.

Preconception planning can help:

  • Assess your risks of pregnancy and reduce those risks
  • Determine your thyroid hormone levels and adjust medications, as needed

Potential Pregnancy Complications

Hypothyroidism Complications:

Women with untreated hypothyroidism are at increased risk of complications that include:

  • Infertility
  • Anemia
  • Preeclampsia
  • Placental abruption
  • Premature birth
  • Low birth weight
  • Problems with fetal brain development
  • Postpartum hemorrhage
  • Miscarriage
  • Stillbirth

Hyperthyroidism Complications:

Women with untreated hyperthyroidism are at increased risk of pregnancy complications that include:

  • Congestive heart failure
  • Preeclampsia
  • Premature birth
  • Fetal growth problems
  • Low birth weight
  • Thyroid storm, a sudden, severe worsening of symptoms
  • Fetal tachycardia, an abnormally fast heart rate in the fetus
  • Fetal hyperthyroidism or neonatal hyperthyroidism (in women with autoimmune disease)
  • Miscarriage
  • Stillbirth

Causes of Thyroid Disease in Pregnancy

Hypothyroidism in pregnancy may be caused by:

  • Hashimoto’s disease, a form of thyroiditis (inflammation of the thyroid gland) where the immune system attacks the thyroid and interferes with the production of thyroid hormones
  • Inadequate treatment of preexisting hypothyroidism
  • Prior thyroid removal or destruction, for treatment of hyperthyroidism
  • Iodine deficiency

Hyperthyroidism in pregnancy may be caused by:

  • Graves’ disease, an autoimmune disorder that causes the thyroid to make too much thyroid hormone
  • Medication for treatment of hypothyroidism that can lead to symptoms of an overactive thyroid
  • Thyroid nodules that produce excess thyroid hormone 

Symptoms of Thyroid Disease in Pregnancy

Symptoms of hypothyroidism may include:

  • Extreme fatigue
  • Weakness
  • Muscle aches
  • Abnormal weight gain
  • Feeling cold
  • Constipation
  • Hair loss
  • Puffiness around the eyes
  • Memory or concentration problems

Symptoms of hyperthyroidism may include:

  • Enlarged thyroid gland (goiter)
  • Fatigue
  • Weight loss or failure to gain normal pregnancy weight
  • Rapid or irregular heart beat
  • Increased sweating/sensitivity to heat
  • Nervousness
  • Sudden shortness of breath
  • Slight tremor
  • Eye problems including wide-eyed stare, bulging eyes or puffiness
  • Severe nausea and vomiting

Diagnosing Thyroid Disease in Pregnancy

A diagnosis of thyroid disease is based on:

  • A thorough physical exam
  • Careful review of your symptoms
  • Blood tests to measure thyroid hormone levels
  • Ultrasound of the thyroid, as needed

Diagnosing thyroid conditions can be challenging because the symptoms are often similar to the normal signs and symptoms of pregnancy. Interpreting blood test results can be equally challenging because of normal hormonal changes during pregnancy.

Treatment of Thyroid Disease in Pregnancy

Treatment will depend on your specific thyroid condition, your health and the health of your unborn baby. All women with thyroid disease should be closely monitored throughout pregnancy, with frequent blood tests to measure thyroid function and adjust medications, as needed. Fetal growth and development should also be monitored.

Hypothyroidism Treatment:

Hypothyroidism, or underactive thyroid, is treated with synthetic (man-made) thyroid hormones to replace what the body isn’t producing. These medications are also known as thyroid replacement hormones.

Hyperthyroidism Treatment

Treatment of hyperthyroidism, or overactive thyroid, may include:

  • Anti-thyroid medications to reduce the amount of thyroid hormone being produced, using the minimum effective dosage; these medications can also decrease thyroid hormone function in the fetus, resulting in hypothyroidism in the baby
  • Surgery, in rare cases, to remove part of the thyroid
  • Monitoring of the fetus for possible signs of hyperthyroidism
  • Treatment or testing with radioactive iodine should be strictly avoided during pregnancy

The Benefits of Specialized Care

Texas Children’s Pavilion for Women offers specialized care to help women with thyroid disease achieve the safest, healthiest pregnancy possible.

Our obstetric providers are trained and experienced in the evaluation and management of these complex pregnancies, carefully assessing and balancing the treatment needs of the mother with the health and safety of her unborn baby.

We offer: