Many pregnant women do not meet iodine intake requirements

May 10, 2013

According to a new data analysis, the majority of pregnant women in the US may have an inadequate iodine status and insufficient intakes from dietary supplements.

The analysis of data from a representative US population-based survey examined the iodine intake (based on urinary iodine concentrations) of 1,250 pregnant women and 5,154 women of reproductive age (between 15 and 39 years of age), and estimated their iodine intake from dietary supplements (1). The results showed that the median urinary iodine concentration (UIC) in the pregnant participants was 148 mcg/L, which has been defined as insufficient by the WHO (below 150 mcg/L). Although 77.5% of pregnant women reported taking one or more dietary supplements in the past 30 days, only 22.3% consumed an iodine-containing supplement. They had an estimated mean daily iodine intake of 122 mg from supplements (median value 144 mg/day). Among non-pregnant women who reported using supplements with iodine, the estimated mean daily iodine intake from supplements was 107 mg and the median UIC was 133 mcg/L, with 100 to 199 mcg/L defined as adequate.

The researchers commented that, because iodine is available in very few foods, dietary supplements may play a key role in ensuring that the population – particularly pregnant and non-pregnant women of child-bearing age and other subgroups at risk in the population – receives enough iodine for optimal health and optimal fetal development. Iodine is essential for adequate fetal and postnatal central nervous system growth and development. It is important to determine the iodine intake and status of both pregnant and non-pregnant women of reproductive age because the critical period of organogenesis comes before many women know that they are pregnant. The iodine requirement increases by over 50% during pregnancy. Iodine deficiency is the most frequent cause of preventable mental retar-dation globally. Although the burden of iodine deficiency in the US is lower than that in the developing world, it is still an important public health issue because some subgroups of pregnant and reproductive-aged women are still at risk for mild deficiency (2). The WHO defines iodine sufficiency in pregnancy as a median UIC of 150 to 249 mcg/L (3).


  1. Gahche J. J. et al. The Prevalence of Using Iodine-Containing Supplements Is Low among Reproductive-Age Women, National Health and Nutrition Examination Survey 1999–2006. The Journal of Nutrition. Published online April 2013.
  2. Perrine C. G. et al. Some subgroups of reproductive age women in the United States may be at risk for iodine deficiency. J Nutr. 2010; 140:1489–1494.
  3. WHO. United Nations Children’s Fund and International Council for the Control of Iodine Deficiency Disorders. Assessment of iodine deficiency disorders and monitoring their elimination, a guide for programme managers. 3rd ed.; 2007.