Iodine Deficiency to Iodine Excess: Have We Come Full Circle?

ABSTRACT

Objective: Recent studies have demonstrated an increase in the prevalence of hypothyroidism among pregnant women. Since hypothyroidism during pregnancy may increase fetomaternal morbidity, it is imperative to study the reason underlying this condition. Therefore, the present study was aimed to assess the iodine status in pregnant women and its correlation with hypothyroidism. Material and Methods: The present study was designed as a cross-sectional study to detect thyroid dysfunction in pregnant women in a tertiary-care hospital setting. Detailed demographics and the medical and obstetric history of the included subjects were recorded, and their baseline serum thyrotropin (TSH) and urinary iodine levels were determined. The women diagnosed with hypothyroidism were subjected to reflex testing for thyroid peroxidase antibodies (TPOAb). Results: The Median Urinary Iodine concentration of the study population, determined using the spot urinary iodine concentration of 545 women, was 255μg/L, which was higher than the level recommended in the WHO Guidelines. Among the 33% women (n=180) detected to be hypothyroid (TSH level >2.5mIU/L in the 1st trimester or >3.0mIU/L in the 2nd or 3rd trimester), 32% women (n=67) were positive for TPOAb. The correlation between the TSH levels and the urinary iodine levels was not significant (p=0.688); a significant correlation was observed between the urinary iodine levels and positivity for TPOAb (p=0.047). Conclusion: The current iodine status among pregnant North Indian women indicates a trend toward Iodine excess, with a significant association with the high prevalence of thyroid autoimmunity in the study population.