An article on Medical News Today provides evidence from an upcoming research paper in The Journal of Pediatrics, that taking iodine supplements during pregnancy may be associated with hypothyroidism at birth (thyroid hormone deficiency) and left untreated, may lead to neurocognitive impairments of the child.
The study was based on three infants born with the condition after their mothers took 12.5mg of iodine per day. That is 11 times the levels doctors say are safe. The iodine was taken during pregnancy and/or while breastfeeding, and passed into the infant through placenta or milk respectively. These babies had 10 times the level of healthy infants.
Read the article.