Urinary iodine deficiency in Gippsland pregnant women: the failure of bread fortification?

Objective: To assess iodine status and the factors that influence iodine status among a cohort of pregnant women living in Gippsland.

Design, Participants And Setting: Cross-sectional study of 86 pregnant women (at ≥ 28 weeks' gestation) conducted in hospital antenatal care services and private obstetrician clinics across the Gippsland region of Victoria, Australia, from 13 January 2009 to 17 February 2010.

Main Outcome Measures: Overall proportion of pregnant women with a urinary iodine concentration (UIC) > 150 μg/L; proportion of pregnant women with a UIC >150 μg/L after the mandatory iodine fortification of bread; use of supplements containing iodine; intake of foods known to be good sources of iodine; intake of bread.

Results: The percentage of pregnant women with UIC >150 μg/L (indicative of iodine sufficiency) was 28%. There was no statistically significant difference in UICs before and since iodine fortification of bread. The median UIC before fortification was 96 μg/L (interquartile range [IQR], 45-153 μg/L) and since fortification was 95.5 μg/L (IQR, 60-156 μg/L). The dietary intake of iodine-rich food (including bread) and the use of appropriate supplements was insufficient to meet the increased iodine requirements during pregnancy.

Conclusions: The UICs in this cohort of pregnant women are of concern, and seem unlikely to be improved by the national iodine fortification program. Pregnant women in Gippsland urgently need effective iodine education programs and encouragement to either consume iodine-rich foods or take appropriate supplements.