Final answer:
Normal T4 levels in newborns are generally higher than in adults, with hypothyroidism treated by thyroid hormone replacement therapy, typically with levothyroxine, to avoid cognitive and developmental delays.
Step-by-step explanation:
The normal range of T4 (thyroxine) levels in newborns varies, but is typically higher than in adults due to the demands of early development. While normal ranges may differ slightly depending on the laboratory and testing methods, a significant deviation from the average suggests the need for further investigation.
If a newborn is diagnosed with hypothyroidism, which is indicated by abnormally low levels of thyroid hormones, treatment is critical to ensure normal development. Treatment commonly involves thyroid hormone replacement therapy, typically with a synthetic form of thyroxine known as levothyroxine. This medication will likely be needed for the entirety of the individual's life to maintain normal thyroid hormone levels, thus avoiding the severe consequences of hypothyroidism such as cognitive deficits and growth delays. The thyroid hormone plays a vital role in brain maturation, and deficiencies can lead to irreversible harm. It's essential that hypothyroidism in newborns is diagnosed and treated swiftly to ensure the best possible outcomes.