Hormones are chemical messengers that are secreted by glands and regulate many functions as part of the endocrine system in the body.
The endocrine system has a complex system of checks and balances to make sure that hormone levels in the body are at normal levels. Hormone disorders occur when a gland produces too much or too little of a hormone. Hormone disorders can be caused by many things, including being exposed to certain chemicals in the environment. For more information, see Hormone Disorders and the Environment
The thyroid is one of the major glands of the endocrine system. The thyroid is a butterfly-shaped gland located just below the Adam's apple. The hormones the thyroid produces primarily control metabolism. Their levels can affect a person's physical energy, temperature, weight, and mood. Most thyroid disorders are usually related to the gland producing too little thyroid hormone (hypothyroidism) or too much thyroid hormone (hyperthyroidism), and can be treated.
Congenital hypothyroidism (CH) occurs when a baby is born without the ability to produce adequate thyroid hormone. This can be caused by a defect in the gland, issues with thyroid metabolism, or an iodine deficiency. Thyroid hormones are essential for healthy growth and brain development, so newborn screening programs test for CH at birth. Children with CH can lead healthy lives with treatment.