Research paper
Systematic review and meta-analysis of the effects of iodine supplementation on thyroid function and child neurodevelopment in mildly-to-moderately iodine-deficient pregnant women.
Study answer
What this study found
Overall, the evidence was insufficient to support routine iodine supplementation during pregnancy in mildly-to-moderately iodine-deficient women. Some studies suggested improved maternal thyroid biomarkers, especially lower thyroglobulin and smaller thyroid-volume increases, but effects on TSH and free thyroxine were inconsistent. In the pooled RCT data, maternal TSH, FT4, and Tg showed small changes during pregnancy, but child neurodevelopment did not improve: meta-analysis of 2 RCTs found no effect on cognitive, language, or motor scores. The sole adequately powered trial also found no…
- Study & population
- Systematic review and meta-analysis of 37 publications evaluating pregnant women with mild-to-moderate iodine deficiency, mainly from Europe with additional studies from Asia, Australia, and other regions.
- Intervention
- Iodine supplementation during pregnancy, generally given orally as potassium iodide or iodine-containing multivitamin/mineral tablets, with doses in the included trials ranging from 50 to 300 μg/day and most randomized comparisons using 150 to 225 μg/day from early pregnancy through late gestation or term.
- Key limitation
- The evidence base was heterogeneous in design, dosing, timing of initiation, baseline iodine status, and outcome measurement, limiting comparability across studies.
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Open PDFOriginal abstract
BACKGROUND Mild-to-moderate iodine deficiency, particularly in pregnancy, is prevalent; this is of concern because observational studies have shown negative associations with child neurodevelopment. Although neither the benefits nor the safety of iod…