(HealthDay News) – Even mild iodine deficiency during pregnancy can have long-term adverse effects on a child’s cognition, according to a study published in the May 1 issue of the Journal of Clinical Endocrinology & Metabolism.

Kristen L. Hynes, PhD, from the University of Tasmania in Sandy Bay, Australia, and colleagues conducted a longitudinal follow-up of the Gestational Iodine Cohort, a group in which pregnancy occurred during a period of mild iodine deficiency in the population (1999–2001). The children subsequently grew up in an iodine-replete environment and were evaluated at age 9 years, in Year 3, using Australian national curriculum and Tasmanian state curriculum educational assessment data.

The researchers found that, compared with children whose mothers had a urinary iodine concentration (UIC) of ≥150µg/L, children whose mothers had a UIC <150µg/L had significant reductions of 10% in spelling, 7.6% in grammar, and 5.7% in English-literacy performance. Even after adjustment for a range of biological factors, including maternal age at birth of child, gestational length at time of birth, gestational age at the time of urinary iodine collection, birth-weight, and sex, the correlations remained significant. After further adjustment for socioeconomic factors, including maternal occupation and education, the differences in spelling remained significant.

“This study provides preliminary evidence that even mild iodine deficiency during pregnancy can have long term adverse impacts on fetal neuro-cognition that are not ameliorated by iodine sufficiency during childhood,” the authors write.

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