The connection has been known for years, and yet most pregnant women are iodine deficient, expert says

The evidence is in. Iodine deficiency during pregnancy may cause obstetric complications in mothers and irreversible brain disorders in infants and newborns. All GPs should test for thyroid function and prescribe iodine supplements as necessary, says University of Sydney clinician, endocrinologist and researcher Professor Cres Eastman.

“The commonest cause of preventable neurodevelopmental defects or disability in our world is iodine deficiency,” says Professor Eastman, pointing to the 2008 World Health Organization assessment.

As chair of the Australian Centre for Control of Iodine Deficiency Disorders and former head of the Institute for Clinical Pathology and Medical Research at Westmead Hospital, Professor Eastman says “there are dozens and dozens, if not hundreds of papers, systematic reviews and meta analyses showing that maternal subclinical hypothyroidism triggered by iodine deficiency or autoimmune thyroiditis is risky for mums and bubs”.

Iodine is critical because it is a key component of the thyroid hormones tri-iodothyronine (T3) and thyroxine (T4). They regulate functions during pregnancy such as placental growth and foetal brain development, Professor Eastman says.

“Comparative studies done in Australia show that if a child is born to a mother who is iodine deficient, compared with a child born to a mother who has an adequate iodine intake, the child will have a lower IQ of about 10%. And that’s a very significant defect. That defect is irreversible. You cannot fix it after birth.”

Moreover, surveys reveal that most pregnant Australian women are iodine deficient, he notes. They need a top-up of 50%.

The National Health and Medical Research Council recommended iodine intake for adults is 150 micrograms per day and 250 micrograms per day during pregnancy.

Supplements are needed as today’s diets no longer contain adequate iodine levels, despite a 2009 federal regulation that salt used in the manufacture of bread and baked products must be iodine-fortified.

So where has all our iodine gone?

According to Professor Eastman, in the “conventional Australian diet, iodine comes mainly from milk and dairy products”.

“Things went sour when the dairy industry quietly stopped using iodine-based sanitisers to clean out milk cans.” Also, many coffee drinkers have switched to non-dairy substitutes like soy milk.

Unfortunately, surveys of pregnant Australian women reveal that nearly half had not heard of the importance of iodine.

Hence, Professor Eastman’s call for GPs to check, supplement and inform their patients of the importance of iodine supplements during pregnancy and breastfeeding.

Professor Eastman will be speaking at The Annual Women’s & Children’s Health Update in Adelaide, Brisbane, Melbourne, Sydney and Perth. Sign up to hear more on this topic, and others such as hormone-related DVT, iron and pregnancy, eating disorders in young people, managing menopause in primary care and more.