How does the thyroid gland develop during early growth?

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Detailed anatomical illustration of the human thyroid gland and surrounding structures, showing the right and left lobes, isthmus, nearby arteries, veins, nerves, lymph nodes, and cartilage in the neck. — thyroid gland Human thyroid gland.

The thyroid gland develops through a downward outpouching from the floor of the pharynx. During this migration, a persisting remnant of the tissue may remain, which is known as a thyroglossal duct.1

In terms of functional development, the fetal thyroid gland begins to function at approximately 12 weeks of gestation, with its activity increasing progressively throughout the remainder of fetal development. Following birth, there is a rapid surge in thyrotropin secretion, leading to a marked increase in the concentration of thyroid hormones, which then gradually decline to reach adult levels by the time of puberty.2