Breast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient women.

Study answer

What this study found

Iodine supplementation modestly improved breast-milk and maternal iodine markers, but the doses tested did not achieve adequate iodine status in mothers or infants. Between weeks 1 and 24, breast-milk iodine concentration fell by 40% in the placebo group (P < 0.001), while it was higher with 75 μg/day versus placebo (1.31 times higher; 95% CI: 1.02, 1.67; P = 0.030) and with 150 μg/day versus placebo (1.69 times higher; 95% CI: 1.32, 2.16; P < 0.001). Maternal urinary iodine concentration also increased with 75 μg/day (2.12 times; 95% CI: 1.61, 2.78; P < 0.001) and 150 μg/day (2.35 times;…

Study & population

Randomized, double-blind, placebo-controlled trial in healthy lactating women in Dunedin, New Zealand.

Intervention

Healthy lactating women received a daily iodine supplement for 24 weeks postpartum: 75 μg/day or 150 μg/day, given as 1 tablet/day of potassium iodate, compared with placebo.

Key limitation

The intervention was tested in small active arms over a relatively short 24-week postpartum period, limiting precision and long-term inference.

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Original abstract