Is it Necessary to Recommend Iodine Supplement to Pregnant Women Living in Areas with Adequate Iodine Intake?

Background: Iodine need is increased during pregnancyandits deficiency can lead to complications in mother andfetus. The latest international guidelines have recommended a higher intake of iodine. Iran has implemented a national salt iodization program since 25 years ago, and the general population is iodine-sufficient. However, recent studies have shown that a significant proportion of pregnant women have urinary iodine concentration (UIC) below the recommended range of 150 - 250 g/L. Based on the results of these studies, iodine supplement during pregnancy is widely used, but this practice is controversial. Objectives: The aim of this study was to evaluate the necessity for iodine supplementation in pregnant women living in Shiraz, an iodine-replete area. Methods: In this cross-sectional case-control study, UIC and thyroid-stimulatinghormoneof 174 pregnantwomentaking 150g/day iodine (group 1) were compared with 124 pregnantwomennot taking the supplement (group 2). The proportion of womenwith UIC below the recommended level in each group was also determined. UIC of the women in different trimesters in each group was also investigated and compared. Results: MeanUIC in groups 1 and 2 was 175.7156.43g/L and 122.544.37g/L and this difference was significant (P = 0.006). Also, 56% of women in group 2 and 24 % in group 1 had UIC below the recommended value (P < 0.01). Mean UIC in both groups decreased with advancing gestational age. In group 1, mean UIC remained in the recommended range, whereas in group 2, it decreased to less than 100 g/L. Conclusions: In areas covered by the national salt iodine implementation program, it is necessary to recommend iodine supplement to pregnant women to prevent iodine insufficiency.