The results are thus compatible with the international recommendation that lactating women and infants younger than two years of age who reside in iodine-sufficient countries do not require iodine supplementation
BACKGROUND Iodine , an essential micronutrient , plays a critical role in normal growth and development , especially during the first two years of life .
This systematic review and meta- analysis is among the first to evaluate breast-milk iodine concentrations and infant iodine status in countries characterized by iodine sufficiency or deficiency .
Breast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient women.
BACKGROUND Little is known about the iodine status of lactating mothers and their infants during the first 6 mo postpartum or , if deficient , the amount of supplemental iodine required to improve status . OBJECTIVE The objective was to determine maternal and infant iodine status and the breast-milk iodine concentration ( BMI C ) over the first 6 mo of breastfeeding . DESIGN A r and omized , double-blind , placebo-controlled supplementation trial was conducted in lactating women who received placebo ( n = 56 ) , 75 μg I/d ( n = 27 ) , or 150 μg I/d ( n = 26 ) after their infants ' birth until 24 wk postpartum .  Maternal and infant urine sample s and breast-milk sample s were collected at 1 , 2 , 4 , 8 , 12 , 16 , 20 , and 24 wk . Maternal serum thyrotropin and free thyroxine concentrations were measured at 24 wk . RESULTS Over 24 wk , the median urinary iodine concentration ( UIC ) of unsupplemented women and their infants ranged from 20 to 41 μg/L and 34 to 49 μg/L , respectively , which indicated iodine deficiency ( ie , UIC < 100 μg/L ) . Mean maternal UIC was 2.1 - 2.4 times higher in supplemented than in unsupplemented women ( P < 0.001 ) but did not differ significantly between the 2 supplemented groups . BMI C in the placebo group decreased by 40 % over 24 wk ( P < 0.001 ) and was 1.3 times and 1.7 times higher in women supplemented with 75 μg I/d ( P = 0.030 ) and 150 μg I/d ( P < 0.001 ) , respectively , than in unsupplemented women . Thyrotropin and free thyroxine did not differ significantly between groups . CONCLUSION BMI C decreased in the first 6 mo in these iodine-deficient lactating women ; supplementation with 75 or 150 μg I/d increased the BMI C but was insufficient to ensure adequate iodine status in women or their infants . The study was registered with the Australian New Zeal and Clinical Trials Registry as ACTRN12605000345684
The results are thus compatible with the international recommendation that lactating women and infants younger than two years of age who reside in iodine-sufficient countries do not require iodine supplementation
BACKGROUND Iodine , an essential micronutrient , plays a critical role in normal growth and development , especially during the first two years of life .
This systematic review and meta- analysis is among the first to evaluate breast-milk iodine concentrations and infant iodine status in countries characterized by iodine sufficiency or deficiency .