Suboptimal Iodine Status of Australian Pregnant Women Reflects Poor Knowledge and Practices Related to Iodine Nutrition

Objective: To assess the iodine status and knowledge and practices related to iodine nutrition of Australian women during pregnancy.

Methods: A cross-sectional study was conducted at a public antenatal clinic in the Illawarra region of New South Wales. One hundred thirty-nine pregnant women across all trimesters provided a spot urine sample (n = 110) and completed a short questionnaire (n = 139) in English. Iodine status was based on World Health Organization/International Committee for the Control of Iodine Deficiency Disorders urine iodine concentration (UIC) categories.

Results: Median UIC was 87.5 μg/L (interquartile range 62); only 14.5% of participants had an adequate UIC value ≥150 μg/L. Fifteen percent of women had very low UIC values (<50 μg/L), whereas 45.5% had values in the 50- to 99-μg/L range. Knowledge of the adverse health effects of an inadequate iodine intake was poor. Approximately half the participants were able to indicate good dietary sources of iodine, such as fish (58%) and iodized salt (51%). However, a high level of confusion regarding other foods was evident. Only a small number of participants (11%) reported that they had intentionally changed their diet to increase iodine intake during pregnancy, but 59% indicated supplement use, of which 35% contained iodine. Those who were taking supplements that contained iodine had significantly higher UIC levels (139.1 μg/L) than those who were not (90.8 μg/L, P < 0.05).

Conclusion: Public health strategies, including nutritional education and supplementation, are urgently required to improve the iodine status of pregnant women. Currently, no readily accessible information on iodine is available to women attending antenatal clinics in Australia.