The thyroid is a gland in the lower neck. It makes hormones that regulate growth, brain development, and metabolism. Hypothyroidism is a low or absent production of these hormones. Congenital means the conditions is present since birth.

The Thyroid Gland
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If this condition is not treated it can cause damage to the brain. This can lead to intellectual disability and abnormal growth.

In most cases, the cause is unknown. The most common known cause is abnormal development of the thyroid gland. A small percentage of cases are inherited.

Babies born before 40 weeks may have a temporary shortage in the thyroid hormones.