01-07-2025
Iodine-deficiency signs in some 60% of pregnant women in Ireland, study finds
Some 60 per cent of pregnant women in Ireland show signs of iodine deficiency, a new study from
University College Cork
has found.
Iodine is essential for thyroid hormone production, which supports a baby's brain development during pregnancy.
A women's requirement for the mineral increases 50 per cent during pregnancy, but it cannot be produced by the human body and must be acquired through the diet or supplements.
The researchers of the study, which is the first large-scale assessment of iodine status in pregnant women in Ireland, said the findings highlight a need for increased nutritional awareness to support maternal and child health.
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The study, which was recently published in the European Journal of Nutrition, evaluated iodine levels in more than 1,500 women who were pregnant with their first baby at Cork University Maternity Hospital, through health questionnaires and urine samples.
The study found 60 per cent of participants had insufficient iodine intake. The average urinary iodine concentration (UIC) was 125µg/L (micrograms per litre), below the World Health Organisation (WHO) recommended level of 150µg/L for pregnancy, the study said.
Women who were younger, had a higher BMI, had lower education levels or were not taking iodine-containing supplements were more likely to be deficient, the report added. Seasonal variation played a role, with lower iodine levels during the summer months.
The research was led by Dr Áine Hennessy from the Irish Centre for Maternal and Child Health Research (INFANT) at UCC and the Cork Centre for Vitamin D and Nutrition Research at the School of Food and Nutritional Sciences.
According to the researchers, deficiency of iodine in pregnancy can lead to adverse outcomes, including impaired neurodevelopment in children.
Dr Hennessy said iodine deficiency is
'
one of the most common micronutrient deficiencies worldwide'.
'There is little public awareness of the important role that iodine plays in brain development during pregnancy,' she said.
'Our findings are particularly concerning as most women in the study were considered healthy and low risk and two-thirds reported taking pregnancy supplements containing iodine. This suggests that additional public health measures may need to be addressed.'
Dr Hennessy has advised women planning a pregnancy to ensure 'adequate iodine intake through diet'.
'Including two or more servings of milk or yoghurt daily and eating white fish once a week is recommended by the HSE,' she said.
'For those following vegan or predominantly plant-based diets, it's important to choose iodine-fortified alternatives. We do not recommend kelp or seaweed supplements, as they can contain very high levels of iodine that can cause issues for the thyroid.'
The researchers have called for a 'policy review' and nutrition education for women of childbearing age, noting Ireland does not currently have a policy for salt iodisation or iodine food fortification.
Iodisation is the process of fortifying salt for human consumption with iodine and is an effective strategy to increase iodine intake, according to the WHO.
