Objective: To identify a level of iodine supplementation to recommend for pregnant and breastfeeding women in Australia.
Design, setting and participants: Dietary modelling indicated that mandatory fortification of bread with iodine by replacing salt with iodised salt would still leave a gap in iodine intakes in pregnant and breastfeeding women in Australia. Iodine shortfall was estimated by two separate methods: (i) analysis of data from published studies reporting mean urinary iodine concentrations in populations of Australian women who were pregnant or had given birth in the past 6 months; and (ii) modelling based on the postmandatory fortification iodine intake estimates calculated by Food Standards Australia New Zealand using food consumption reported by women aged 19-44 years who participated in the 1995 National Nutrition Survey.
Main outcome measure: Estimated level of daily supplementation required to provide sufficient iodine to result in a low proportion of pregnant and breastfeeding women having inadequate iodine intakes.
Results: Estimations from both data sources indicate that a supplement of 100-150 μg/day would increase iodine intakes to a suitable extent in pregnant and breastfeeding women in Australia.
Conclusions: The final level of supplementation we recommend should be based on these calculations and other factors. There will be population subgroups for whom our general recommendation is not appropriate.