Final answer:
The nurse should inform the parents that their infant with congenital hypothyroidism will require lifelong thyroid hormone replacement medication to prevent cognitive deficits and support normal development.
Step-by-step explanation:
A nurse teaching the parents of an infant who has congenital hypothyroidism should explain that thyroid hormone replacement therapy will be crucial for the child’s development. The correct statement the nurse should make is: "Your baby will need to take thyroid hormone replacement medication for life." This is because thyroid hormones are critical for brain maturation, and insufficient levels can lead to cognitive deficits and other serious consequences like cretinism, which is characterized by impaired growth and mental development.
It is crucial to monitor and adjust the level of replacement thyroid hormone as needed because an imbalance can lead to various symptoms. It's also important to note that dietary iodine is essential for thyroid hormone production, but in cases of hypothyroidism not caused by iodine deficiency, such as Hashimoto's thyroiditis, increasing iodine intake would not resolve the condition.
Therefore, the options about restricting fluids, using soy-based formula, and the baby outgrowing the condition are incorrect.