Indian Journal of Neonatal Medicine and Research. 2017 Apr, Vol-5(2): PL01-PL02 DOI: 10.7860/IJNMR/2017/27126.2208 1 Letter to Editor Paediatrics Section Sir, We read an original article titled “A Community Based Survey on Prevalence of Iodine Deficiency among Pregnant Women in a Municipality Area of West Bengal, India” (2016 Oct, Vol- 4(4): PO10-PO13) in Community paediatrics section in your renowned journal – IJNMR. In the study, investigators assessed the prevalence of iodine deficiency among pregnant women by measuring urinary iodine level. The study was carried out in a municipality area in South 24 Paraganas district which is an iodine-repleted area in West Bengal. Study by Sen TK et al., in another district of West Bengal - North 24 Parganas showed that 72.9 percent households were consuming adequately iodized salt [1]. Study by Majumder A et al., studied the prevalence of iodine deficiency among pregnant and lactating women in Kolkata and found that salt iodination program was adequate for general population but not adequate for pregnant and lactating mothers [2]. District wise fact sheet of National Family Health Survey – 4 (2015-2016) showed that 94.6 percent household use iodized salt in South 24 Parganas district [3]. The districts of West Bengal where these studies were carried out are shown in [Table/Fig 1]. Hence, from these studies and survey, it is evident that the fortification of salt with iodine is adequate in these three adjacent districts of West Bengal. From these data, it can be assumed that dietary source of Iodine for pregnant women were similar as of general population. Maternal hypothyroidism, even a mild-low T4 level or elevated TSH level may cause cognitive delay in babies because thyroid hormone is essential for neurodevelopment. During pregnancy, the demand of iodine is increased as the thyroid hormone production is increased. The underlying reasons for increased thyroid hormone synthesis in pregnancy are – 1) Increased levels of serum thyroxine-binding globulin, 2) Thyrotropin receptor stimulation by human chorionic gonadotropin hormone, and Iodine Deficiency in Pregnancy and Challenges to Measure the Level of Deficiency 3) Initiation of fetal thyroid hormone production in second half of pregnancy [4]. Hence, WHO recommends increased dietary intake of iodine during pregnancy (250 μg/day) whereas, for non-pregnant woman the recommended daily intake is 150 μg/day. So, increased demand may be a contributing factor for decreased urinary excretion of iodine found in the study of discussion. Another factor to consider is - increased Glomerular Filtration Rate (GFR) in pregnancy. Renal iodine clearance depends on GFR as there is no evidence of tubular secretion,and reabsorption is partial, passive and decreased by osmotic HIMEL MONDAL, SHAIKAT MONDAL [Table/Fig-1]: Districts of West Bengal where studies were carried out. * Map is not according to accurate scale.