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Excessive iodine consumption during pregnancy increases babies' risk of hypothyroidism

Category: General Wellness

A series of studies published in The Journal of Pediatrics suggests that babies are more likely to develop congenital hypothyroidism if their mothers consumed excessive amounts of iodine during pregnancy. A lab test can help expectant women figure out whether they have healthy levels of this nutrient.

In order to support normal development of the fetal thyroid gland, the World Health Organization recommends that pregnant women consume 200 to 300 micrograms of iodine a day. Meanwhile, the U.S. Institute of Medicine designated the safe upper limit of iodine at 1,100 micrograms. Sources of this mineral include seaweed, prenatal vitamins and dietary supplements.

For the new series of studies, researchers across the U.S. discuss three infants who developed congenital hypothyroidism because their mothers consumed 11 times the safe upper limit of iodine while pregnant or nursing.

Although the thyroid glands of adults and older children are able to protect themselves from excessive iodine, the same is not true for infants.

"The use of iodine-containing supplements in pregnancy and while breastfeeding is recommended in the United States. However, these cases demonstrate the potential hazard of exceeding the safe upper limit for daily ingestion," said researcher Kara Connelly, M.D.

Pregnant women who are concerned about their iodine may undergo a lab test to check their blood levels of the substance.