Congenital hypothyroidism

Congenital hypothyroidism (CH) is a condition present at birth in which the thyroid gland does not produce sufficient amounts of thyroid hormones, which are critical for normal growth, brain development, and metabolism. It is one of the most common preventable causes of intellectual disability. The condition may result from thyroid dysgenesis (absent, ectopic, or hypoplastic thyroid gland), which accounts for approximately 80-85% of cases, or from thyroid dyshormonogenesis (defects in thyroid hormone synthesis), which accounts for 10-15% of cases. Rarely, congenital hypothyroidism can be caused by central (hypothalamic-pituitary) defects. Synonyms include congenital myxedema and cretinism (a historical term now considered outdated). In the newborn period, symptoms may be subtle or absent, which is why newborn screening programs are essential for early detection. When present, clinical features can include prolonged jaundice, feeding difficulties, constipation, a hoarse cry, hypotonia (decreased muscle tone), a large anterior fontanelle, macroglossia (enlarged tongue), umbilical hernia, dry skin, hypothermia, and lethargy. If left untreated, congenital hypothyroidism leads to severe and irreversible intellectual disability, growth failure (short stature), delayed skeletal maturation, and coarse facial features. The primary treatment is lifelong thyroid hormone replacement therapy with levothyroxine (L-T4), which should be initiated as soon as possible after diagnosis — ideally within the first two weeks of life — to optimize neurodevelopmental outcomes. With early detection through newborn screening and prompt, adequate treatment, children with congenital hypothyroidism can achieve normal or near-normal cognitive development and growth. Regular monitoring of thyroid function tests (TSH and free T4) is essential to ensure appropriate dosing throughout childhood and into adulthood. Some forms of congenital hypothyroidism, particularly mild cases or those associated with a eutopic gland, may be transient and can be re-evaluated after age 3 years.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Congenital hypothyroidism