Tasmanian Women remain at risk of Iodine Deficiency during pregnancy

Sunday, 31 March 2019 - 6:47pm

Recent Tasmanian research has highlighted the importance of starting an iodine supplement prior to conception and taking the recommended dose throughout pregnancy to ensure an adequate supply to prevent brain damage to the unborn child.

The study, funded by Tasmanian Community Fund and the Royal Hobart Hospital Research Foundation grants (published in the journal Nutrients) underlines the importance of following the National Health and Medical Research Council (NHMRC) recommendations for iodine supplementation.

This latest finding marks 20 years of iodine deficiency research conducted by a small team of researchers from the University of Tasmania’s Menzies Institute for Medical Research, the Department of Health, and the Royal Hobart Hospital, led by Dr Kristen Hynes, Ms Judy Seal and Professor John Burgess. Their important work has impacted both local and national public health policies and led to research findings of international significance.

Tasmania has long been recognised as a region of endemic iodine deficiency, with “goitre tablets” given weekly at school during the 1950s and ‘60s. A series of surveys in the late 1990’s, indicting a re-emergence of iodine deficiency, led to salt used in breadmaking being replaced with iodised salt in 2001. In 2009, the success of this Tasmanian initiative, which returned the general population to a state of iodine sufficiency, was extended to mainland Australia and New Zealand, with legislation introduced to make the fortification mandatory.

Iodine is an essential micronutrient used by the thyroid gland to make hormones involved in a range of biological processes. It is well established that severe iodine deficiency can lead to spontaneous abortion, stillbirth and congenital abnormalities. Research, including a land-mark study led by Dr Hynes, indicates however that even mild iodine deficiency during pregnancy can have long-lasting negative impacts on the offspring, including poorer performance in literacy, reductions in IQ and decreased language skills.

During pregnancy iodine requirements increase by approximately 50% to meet the needs of the mother and to ensure an adequate supply for optimal brain development of the unborn child. In regions of borderline iodine deficiency, like Tasmania, it is vital that women of child-bearing age have a diet that includes foods which are good sources of iodine, including dairy products, seafood and fortified bread.

While bread fortification has assisted most in the population to have adequate iodine intake, it is unlikely to be enough to meet the additional demand of pregnancy. The NHMRC therefore recommend a daily iodine supplement when planning and throughout pregnancy. This helps to ensure that thyroid stores are adequate from conception onward. The study found that women who did not take an iodine supplement pre-conception and throughout pregnancy were more likely to have iodine levels below the optimal range recommended by the World Health Organisation.

Education of women and those who care for them during pregnancy is vital to raise awareness of the NHMRC recommendations for a daily supplement of 150 micrograms of iodine prior to and throughout pregnancy. Dr Hynes’ team has shown that even transient short-term iodine deficiency during pregnancy can lead to irreversible long term, yet preventable, impacts on children.

Current advice for iodine supplementation pre-conception and during pregnancy can be found at: