Iodine Status of Pregnant Women in Bulgaria

Universal iodization of salt on the whole territory in Bulgaria was introduced in 1994. The external evaluation of an International expert group conducted in 2005, placed the country among those who successfully overcame the problem of iodine deficiency. AIM of the present study is to update the data on iodine intake of pregnant women in Bulgaria, given that there have been no studies in the last 8 years. MATERIAL: A total number of 537 pregnant women were recruited in the study with an average age 30.49±5 y, distributed by gestational weeks and according to the intake of (vitamins and minerals preparations) preparations containing vitamins with minerals. The study was conducted as a cross-sectional, multicenter population-based in 10 regions of Bulgaria (a total of 84 settlements), without pre-selection and 98.3% of the examined pregnant women use Bulgarian iodized salt according to the data from the Questionnaire. METHOD: A spot morning urine samples were collected for determination of urinary iodine concentration. The frozen samples in a special container were transported to the accredited Limbach laboratory in Heidelberg, Germany. The iodine in urine was determined by inductively coupled plasma mass spectrometry (ICP-MS) method. The statistical analysis was performed using standard SPSS 13.0 for Windows. RESULTS: The median urinary iodine concentration (mUIC) for the whole group of pregnant women (n-537) was 170 µg/L (95% CI 161.00 - 177.00). Normal iodine excretion is present in 39.3%, low – in 41.2% and over-optimal – in 19.6% of pregnant women. Significantly lower levels of iodine in urine were found in the third trimester of pregnancy compared to the first trimester (P < 0.012) and compared to the second trimester (P < 0.001). The median iodine concentration in pregnant women from the group supplemented with combined vitamins with minerals was significantly higher compared to the group without supplementation – 175 (95% CI 166.00 - 199.00) against 149 (95% CI 123.00 - 168.00), P < 0.021. CONCLUSION: During pregnancy, additional supplementation with combined vitamins with minerals containing iodine is required, regardless of the universal iodization of salt, introduced in Bulgaria for more than twenty-five years.