A case for universal salt iodisation to correct iodine deficiency in pregnancy: another salutary lesson from Tasmania

Abstract

OBJECTIVE: To assess the impact of iodine fortification of bread on the iodine status of pregnant women, and to determine if studies of iodine levels in school-age children were indicative of women's gestational iodine status. DESIGN: Urinary iodine surveys of pregnant Tasmanian women before and after bread was fortified with iodine in October 2001. PARTICIPANTS AND SETTING: 285 women attending the Royal Hobart Hospital (RHH) antenatal clinic from 1 October 2000 to 30 September 2001 and 517 women attending the RHH antenatal clinic or primary health care centres in 2003-2006. MAIN OUTCOME MEASURES: Median urinary iodine concentration (UIC) for comparison against the World Health Organization recommendation of of 150-249 microg/L for pregnant women. RESULTS: Before supplementation, the median UIC of the 285 women attending the RHH antenatal clinic was 76 microg/L. After supplementation, median UICs were 81 microg/L for 288 women attending primary health care centres and 86 microg/L for 229 women attending the RHH antenatal clinic. Differences in mean UIC were not significant for either the antenatal clinic group (P=0.237) or the primary health care group (P=0.809) compared with the pre-supplementation group. CONCLUSIONS: Iodine deficiency in pregnancy persists despite being corrected in Tasmanian children. Successful iodine supplementation must target reproductive-age and pregnant women and be substantiated by ongoing monitoring during pregnancy and lactation. A robust national program for correcting iodine deficiency is urgently needed. Mandatory universal salt iodisation has international endorsement, and should be considered the preferred strategy for eliminating iodine deficiency in Australia.