Pregnant women have much higher iodine requirements as compared to all other population groups. The National Health and Medical Research Council (NHMRC) recommends pregnant women take a daily iodine supplement of 150 μg to meet their high iodine requirements.

To investigate iodine supplement use and health knowledge among pregnant women.

A cross‐sectional sample of 200 pregnant women aged 18 years or older, in their third trimester based in Gippsland (Victoria, Australia) undertook a self‐administered questionnaire from August 2011–May 2012. The women were recruited from antenatal classes and clinics from all birthing hospitals across Gippsland. Data were analysed using descriptive statistics and logistic regression.

A total of 46% of participants did not follow the NHMRC recommendation of 150 μg/day iodine supplement. The participants lacked knowledge about iodine and the need for supplementation. Only 18.5% of pregnant women believed they needed an iodine supplement. The majority of participants (83.5%) indicated their medical practitioners were the main source of health information, yet only 34.5% indicated being made aware of the importance of increasing iodine intake during pregnancy by their medical practitioner. The predictors of iodine supplementation are general supplementation use and knowledge of the importance of iodine.

Despite NHMRC guidelines for iodine supplementation during pregnancy, many women were not taking a sufficient iodine supplement. Pregnant women may be inclined to take an iodine supplement if they had greater knowledge of their increased iodine needs during pregnancy. Medical practitioners are best placed to provide this information to pregnant women.