Urinary and Milk Iodine Status in Neonates and Their Mothers during Congenital Hypothyroidism Screening Program in Eastern Azerbaijan: A Pilot Study

BACKGROUND: Iodine is essential element in thyroid hormones synthesis and normal growth and development of the brain. Milk and iodine concentrations can be appropriate indicator of body iodine status; in this study, we evaluated the concentrations of urine and milk iodine in newborns and their mothers. METHODS: In a cross-sectional study conducted in 2013, urine and milk iodine in 106 neonates and their mothers referred to healthcare center in Shabestar, Eastern Azerbaijan for congenital hypothyroidism screening program were determined. Median urinary iodine < 100 µg/L and milk iodine < 50 µg/L was considered as iodine deficiency. RESULTS: The median urine iodine concentrations (UIC) in mothers and infants were 142.31 µg/L (.0 - 1260) and 306.76 µg/L (23.56-1020) respectively. Urine iodine concentrations were < 100 µg/L in 33.9% of mothers and 14.2% of neonates. The median milk iodine concentration (MIC) was 58.23 µg/L (20.31- 425) and in 41.9% of mothers was <50 µg/L. A positive significant correlation was found between milk iodine and maternal urinary iodine concentration (r=0.533, P= 0.000). There was significant correlation between neonatal UIC and maternal UIC (r=0.462, P= 0.000), neonatal UIC and MIC (r=0.414, P= 0.000). CONCLUSIONS: Urinary and milk iodine concentrations in mothers and infants were within acceptable range, which indicates adequate iodine intake. However, there were moderate and marginal iodine deficiencies in about half percentage of participants. Insufficient amount of milk iodine in about half of the mothers can result in iodine deficiency in breast-fed infants.