Thyroid hormones influence both the health of the mother as well as the development of the baby. In Germany, children are still being born whose mental and physical development has not been optimum because the mother suffered from an imbalance of the thyroid function (overactive or underactive thyroid) during pregnancy, which has gone undetected and/or untreated. If the mother does not have a sufficient iodine intake during the pregnancy then she and her baby may develop goitre. Happily, congenital goitre is a rarity nowadays (around 1%) because the intake of iodine as part of nutrition has increased in recent years. However, it is still not optimum.
An underactive thyroid in newborns is seen in approx. 1 in every 3000 births, and is therefore the most common congenital metabolic illness.