Thyroiditis. Thyroiditis is an inflammation Thyroid Factor Review of the thyroid, caused usually by an autoimmune attack or a viral infection.Drugs such as lithium can prevent the gland from producing the necessary hormones.

Too much or too little iodine intake. The gland must have iodine to produce enough hormones. Taking too much iodine, however, may cause or worsen hypothyroidism.

If thyroid gland didn't evolve properly whilst in the womb, the child is being born with disproportionate abdomen, enlarged tongue and weakness of muscles. Mild cases of thyroid deficiency very often go unnoticed but baby doesn't develop as normal: may sleep too much and eat too little falling to achieve the optimum of development.
https://usainfo.org/thyroid-factor-review/