What is hypothyroidism?

Approximately one in 100 women of childbearing age has hypothyroidism (a condition marked by an underactive thyroid gland), according to the Endocrine Society. 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. 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, course and dry hair
• course, 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?

It is unclear whether hypothyroidism increases pregnancy loss. Some studies have shown a higher rate of stillbirth and miscarriage, while others found no increase.

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 effects on the fetus. Early studies found that children born to mothers with hypothyroidism during pregnancy had lowered IQ results and impaired psychomotor development. However, recent studies have found that pregnancies with hypothyroidism can have healthy outcomes with treatment.

Whether to screen for thyroid disease or not should be a decision made by the physician and the pregnant woman. Ideally, a woman 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.