Abstract
This study was designed to assess iodine status of mother-fetus dyad by estimation of spot urine iodine concentration (UIC) in the study district. It is a cross sectional study of 250 pregnant women with euthyroid status and their term neonates residing in Dakshina Kannada district. Neonates with fetal growth restriction or requiring intensive care were excluded. Median UIC was quantified using modified Sandell–Kolthoff reaction by microplate method. World Health Organization (WHO) classification was used to categorize iodine status of pregnant women. Among 250 pregnant women, the majority were primigravida (38%). Median maternal thyroid stimulating hormone (TSH) was 1.54mIU/L, and median UIC was 352 mcg/L. Urine iodine levels were insufficient (< 150mcg/L) in 1.2% (n=3), adequate (150-249mcg/L) in 9.2% (n=23) and above requirement (250-499mcg/L) in 89.6% (n=224); none had excess (> 500mcg/L). Median birth weight was 3000 grams and head circumference was 34 cm. Median cord blood TSH was 8.1mIU/L, and median UIC 344.5 mcg/L. All the newborns had adequate (> 100mcg/L) iodine status including those born to mothers with insufficient values. Maternal and newborn median UIC showed positive correlation (r=0.139; p=0.028). Iodine statuses were above requirement or adequate in pregnant women from the study district and their neonates, respectively, indicating successful salt iodization.

Key words: Euthyroid, Salt iodization, Sandell- Kolthoff, Thyroid stimulating hormone.