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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:

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.

Thyroid screening and pregnancy:

The American Association of Clinical Endocrinologists and the Endocrine Society both support thyroid function screenings for all pregnant women. 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. 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:

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.

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Online Resources of High-Risk Pregnancy

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