Impact of Dietary Habit, Iodine Supplementation and Smoking Habit on Urinary Iodine Concentration During Pregnancy in A Catalonia Population

Background: The nutritional status of women during pregnancy can have a considerable effect on maternal and fetal health, and on perinatal outcome. The aim was to assess the changes occurring in dietary iodine intake, KI supplementation, and smoking habit, and the impact of these changes on the urinary iodine concentration (UIC) during pregnancy in a population of women in Catalonia (Spain). Methods: Between 2009-2011 an observational study including a cohort of women whose pregnancy was monitored in the publically-funded health system in a central region of Catalonia. Women received individual educational counseling imparted, a dietary questionnaire was completed, and a urine sample collected for iodine determination at each trimester visit. Results: 633 (67.9%) women answered the questionnaire at all 3 visits. The percentage of women with a desirable UIC (≥150μg/L) increased from the first to the second trimester and remained stable in the third (p<0.001). Analysis of the relationship between UIC≥150 μg/L and the women’s dietary habits showed that the percentage with UIC≥150 μg/L increased with greater consumption of milk, fresh vegetables, and fruit in the first trimester, and the same was true for iodized salt use in all three trimesters and iodine supplementation in all three. Conclusion: During pregnancy increased intake of milk, iodized salt, and iodine supplements was associated with an increase in the UIC.