The nurse caring for a toddler who is diagnosed with congenital hypothyroidism. Which of the following developmental delays should the nurse recognize as the priority concern if the condition is left untreated?

A. Delayed cognitive abilities. Cognitive impairment is the most serious consequence of untreated congenital hypothyroidism. Thyroid hormones are critical for brain development, especially in infancy and early childhood. Severe intellectual disability can result if treatment is delayed, making early diagnosis and levothyroxine therapy essential. B. Delayed social interactions. While social development may be indirectly affected by hypothyroidism due to lethargy, poor responsiveness, or developmental delays, it is not as critical as cognitive delays, which can lead to permanent intellectual disability. C. Delayed language development. Language delays are common in hypothyroidism but often stem from underlying cognitive impairment. Early treatment with thyroid hormone replacement can improve language development over time. D. Delayed motor skills. Hypothyroidism can cause hypotonia (low muscle tone), leading to motor skill delays. However, motor delays are less concerning than irreversible cognitive impairment, which has the most significant long-term impact on the child's quality of life.