Iodine intake during pregnancy, maternal thyroid function and child neuropsychological development


An adequate iodine nutritional status prior to commencement of and during pregnancy is essential for maintaining proper thyroid function and promote maternal fetal brain maturation and neurodevelopment of the child. An adequate intake of iodine is achieved by eating foods rich in this nutrient (fish, dairy products, mainly), and replacing common salt by iodized salt, since long before the mother becomes pregnant.


Recent studies published by researchers INMA in magazines ‘Epidemiology’ and ‘American Journal of Epidemiology’ have studied how it affects the intake of dietary iodine, salt and supplements on maternal thyroid function and neuropsychological development of children per year age. The first study included data from 1844 pregnant women in the cohort of Valencia, Sabadell and Gipuzkoa, while the second included data from 691 mother-child pairs of Valencia.

The results

Contrary to what the authors expected, pregnant women who consumed greater amount of iodine supplement had an increased risk of elevated levels of thyroid stimulating hormone (TSH), indicators of possible thyroid dysfunction. Furthermore, levels of thyroxine (T4), a hormone essential for the proper tioridea fetal development in Gipuzkoa were lower than in the other two areas, this being the highest percentage area of ??supplementation. Moreover, in the cohort of Valencia, by comparing psychological test scores at age, we observed that maternal iodine supplementation did not benefit the psychomotor development of children.

Although data on pregnant women are still scarce and inconclusive, several studies in the general population have shown an association between high iodine intake and hypothyroidism. Although there is consensus that the risks of iodine deficiency are greater than those resulting from excessive drinking, it would be necessary to conduct a surveillance of iodine nutritional status in the population before routinely recommending supplementation during pregnancy.

Object INMA Project study

Currently, from INMA Project is working to expand the results obtained in Valencia on neuropsychological development of the child to other new cohort INMA (Sabadell, Asturias, Gipuzkoa). Additionally, measurements of urinary iodine we have done in mothers after pregnancy INMA will shed light on the variation of this marker among pregnant and nonpregnant women, so you can properly extrapolate existing reomendaciones in the general population.

As proposed by the World Health Organization (WHO), the best strategy to prevent iodine deficiency disorders is the promotion of universal consumption of iodized salt since long before pregnancy, and a balanced diet, avoiding potential damage arising of excessive or uneven.

* Coordination at the time of making the article by Mario Murcia Hinarejos, Area Environment and Health Research Center for Advanced Public Health (CSISP) of Valencia, and Marisa Rebagliato, MD, a specialist in pediatrics and a Master of Health Public, Associate Professor and coordinator of the INMA cohort in Valencia.