Effects of Iodized Salt and Iodine Supplements on Prenatal and Postnatal Growth: A Systematic Review.

Study answer

What this study found

Overall, iodine repletion did not show clear, consistent benefits for prenatal or postnatal somatic growth, and the certainty of evidence was low to very low. A positive birthweight effect was seen only in severely iodine-deficient pregnant women: MD = 200 g; 95% CI: 183, 217 g; n = 635; 2 non-RCTs. Postnatally, iodine improved growth-related biomarkers rather than growth itself, with increases in IGF-1 (MD = 38.48 ng/mL; 95% CI: 6.19, 70.76; n = 498; 2 RCTs) and IGFBP-3 (MD = 0.46 μg/mL; 95% CI: 0.25, 0.66; n = 498; 2 RCTs). The review concludes that more rigorous, adequately powered trials…

Study & population

Systematic review of 18 studies (13 randomized trials, 4 non-randomized trials, and 1 controlled before-after study) including 5729 participants.

Intervention

The interventions evaluated iodine repletion delivered as iodized salt, iodine tablets, iodized oil injections, iodine-containing prenatal multivitamins, and other iodine-fortified vehicles.

Key limitation

Evidence quality was low to very low, and few well-designed trials directly addressed growth outcomes.

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Original abstract