Hormonal control of growth

Whereas earlier growth of the baby is largely influenced by nutrition, increasingly from about 6 months onwards, it becomes dependent on hormonal factors becoming almost completely hormonal driven by the age of 3. The child requires a mixture of hormones to grow, specifically growth hormone and thyroxine.

Growth hormone from the pituitary gland at the base of the brain is one of the most important factors. This acts on the growth plate, epiphyses at the ends of the long bones in the legs and arms, to stimulate bone growth. It does so mainly by stimulating the release of an intermediary growth factor called insulin-like growth factor 1 (IGF).

Thyroxine is produced by the thyroid gland as a result of stimulation by the pituitary gland which secretes thyroid stimulating hormone. This supports growth hormone in stimulating the production of bone cells in the growth plate.

As a general rule, the expected final height of the child is midway between their parents’ two heights and usually partly dependent on their genes. The final height of a child is also dependent on good nutrition and emotional well-being, together with a lack of illnesses or infections occurring in childhood.