Hypothyroidism and Pregnancy

Facts about hypothyroidism and pregnancy

Hypothyroidism is a condition marked by an underactive thyroid gland and may occur during pregnancy. 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 may be 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

• 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 doctor 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. 

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 doctor for a diagnosis.

Who should undergo thyroid function screening?

The American College of Obstetricians and Gynecologists (ACOG) does not recommend thyroid testing as a routine part of prenatal care, but advises that testing should be limited to women with symptoms of thyroid disease and those with a history of thyroid disease or other medical conditions associated with it, such as diabetes. The ACOG recommends that pregnant women who have been diagnosed with thyroid disease be treated throughout pregnancy and during the postpartum period. The American Association of Clinical Endocrinologists recommends that all pregnant women be screened for thyroid problems, but advises women to talk with their doctor about their individual needs.

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.