Hypothyroidism During Pregnancy

Aria Health Center for Gynecology & Women's Health

Facts about hypothyroidism and pregnancy:

 About 3 percent of women of childbearing age has hypothyroidism (a condition marked by an underactive thyroid gland). Unfortunately, many symptoms of hypothyroidism are masked by symptoms of pregnancy, such as fatigue, weight gain, and abnormal menstruation and, as a result, the disease is left undetected and untreated. In addition, the risk for developing hypothyroidism increases with age, which is significant because more and more women are delaying pregnancy until they are older.

What are the symptoms of hypothyroidism?

Hypothyroidism is a common condition, which can go undetected if symptoms are mild. Hypothyroidism means the thyroid is underactive, producing insufficient amounts of thyroid hormones. Symptoms of hypothyroidism are usually very subtle and gradual and may be mistaken for symptoms of depression. The following are the most common symptoms of hypothyroidism. However, each individual may experience symptoms differently. Symptoms may include:

  • dull facial expressions
  • hoarse voice
  • slow speech
  • droopy eyelids
  • puffy and swollen face
  • weight gain
  • constipation
  • sparse, coarse and dry hair
  • coarse, dry, and thickened skin
  • carpal tunnel syndrome (hand tingling or pain)
  • slow pulse
  • muscle cramps
  • orange-colored soles and palms
  • sides of eyebrows thin or fall out
  • confusion
  • increased menstrual flow in women

The symptoms of hypothyroidism may resemble other conditions or medical problems. Always consult your physician for a diagnosis.

How does hypothyroidism affect the fetus?

During the first few months of pregnancy, the fetus relies on the mother for thyroid hormones. Thyroid hormones play an essential part in normal brain development. Deprivation of the maternal thyroid hormones due to hypothyroidism can have devastating effects on the fetus. A study published in the New England Journal of Medicine showed that children born to mothers with hypothyroidism during pregnancy had lowered IQ results and impaired psychomotor development.

Thyroid screening and pregnancy:

The American Association of Clinical Endocrinologists and The Endocrine Society both support thyroid function screenings for all pregnant women. In fact, a study published in the New England Journal of Medicine showed that children born to mothers who had untreated hypothyroidism (underactive thyroid) were more likely to have mental defects. Detection, early in pregnancy, may prevent the harmful effects of maternal hypothyroidism on the fetus.

Ideally, a woman should be tested for a thyroid disorder before becoming pregnant, according to the American Association of Clinical Endocrinologists. If a woman is tested before pregnancy, she is more likely to have thyroid hormone levels in balance throughout her pregnancy.

How is the thyroid function screened?

Screening for hypothyroidism involves a blood test that measures thyroid hormone (thyroxine, or T4) and serum TSH (thyroid-stimulating hormone) levels. Hypothyroidism is often suspected when TSH levels are above normal and T4 levels are below normal. Always consult your physician for a diagnosis.

Who should undergo thyroid function screening?

Although the American Association of Clinical Endocrinologists advises that all pregnant women be screened for thyroid problems, they recommend, specifically, the following:

  • Whether to screen for thyroid disease or not should be a decision made by the physician and the pregnant woman.
  • Anyone considering becoming pregnant should have her thyroid checked in advance.
  • All pregnant women with a family history, or symptoms, of a thyroid disease should be tested.

How is hypothyroidism treated during pregnancy?

Once hypothyroidism is diagnosed, thyroid hormone replacement therapy may be used to treat the mother. Dosage of thyroid hormone replacement therapy is based on the individual's levels of thyroid hormones. The treatment is safe and essential to both mother and fetus. When the fetus is born, routine newborn screening includes a test of thyroid hormone levels.