A new study finds that high maternal thyroid hormone levels during early pregnancy may significantly lower the infant's IQ later in childhood. The study results suggest that the common practice of treating pregnant women who have mild thyroid hormone deficiency may pose unexpected risks to the developing baby's brain. Doctors already know that low thyroid hormone levels in pregnant women are linked to lower child IQ scores as well as other risks to the fetus.
Thyroid hormone supplementation during pregnancy may come with the risk of overtreatment, and even treatment to a high-normal level on thyroid function tests early in pregnancy may not be without risks to the child. The researchers advise physicians to supplement with care. http://www.eurekalert.org/pub_releases/2015-03/tes-hth030515.php
