Frequency distribution of urinary and breast-milk iodine concentrations in postpartum period, Gorgan, 2003

are reliant on adequate maternal iodine intake. The aim of this study was to evaluate iodine sufficiency in lactating women in Iran .

referred to the Taleghani Hospital of Gorgan between April and June 2003. Subjects were within the 1 st -6 th month of their postpartum period. Goiter was graded according to WHO classification. Spot urine ( 2-3 ml) and breast-milk (5-10 ml) samples were collected for the measurement of iodine concentrations using acid digestion method. Urine iodine concentrations ( UIC) of <100 and breast- milk iodine concentrations (MIC) of <50 µg/L were considered as iodine deficiency .

Mean ( ±SD) age of women was 25.6±1.6 years. 43% and 8% had grade 1 and 2 goiters, respectively. The median (range %95 CI) UIC was 259 µg/L (35-519 226-275). UIC of <100 µg/L was detected in 16%, 50-99 in 13% and 20-49 µg/L in 3%. Grade 1 and 2 goiters were present in 8% and 8% of mothers with UIC <100 µg/L, respectively. The median (range %95 CI) MIC was 93.5µg/L (17-696 97- 137). MIC of <50 µg/L was reported in 19%, 35-49 in 13%, 20-34 in 3%, and <20 µg/L in 3%. Grade 1 and 2 goiters were present in 11% and 8% of women with MIC <50 µg/L , respectively. MIC was significantly correlated with UIC levels (r=0.44 , p <0.0001). Meanwhile, there was a significant association between iodine-deficiency and goiter (p <0.0001).

UIC and MIC levels show sufficient iodine supplementation in Gorgan. However, some infants remain at risk for low iodine intake via breast milk .