Early signs of hypothyroidism in the neonate may include which finding?

• A. Growth retardation
• B. Hyperthermia
• C. Hyperlipidemia
• D. Large anterior and posterior fontanelle

Answer: (D)

Congenital hypothyroidism in a newborn often shows signs of delayed bone maturation, which manifests as a fontanelle that remains large for longer than expected. Thyroid hormone is essential for normal ossification and skull growth, so when it’s deficient the anterior fontanelle can be disproportionately large, and the posterior fontanelle may also be prominent. This makes a large fontanelle a classic early clue in affected infants.

Other options don’t fit as well for early neonatal presentation. Growth retardation suggests longer-term growth issues rather than an immediate newborn finding. Hyperthermia goes against the typical cold intolerance and cooler temperature seen in hypothyroid newborns. Hyperlipidemia can occur with hypothyroidism but is not a common early neonatal sign.