Background. Sufficient supply of the population with iodine becomes again a world problem. Particularly the iodine deficiency during pregnancy may have serious negative effects on the foetal development. Estimation of the level of iodine supply of pregnant women became therefore the aim of the study. Investigation was done in the district Teplice. Methods and Results. The cohort was formed by 348 pregnant women (age 17 to 45 years), who received during the pregnancy iodine supplementation in the daily dose of 130 respective 100 mg (Materna, Jod 100). Control group consisted of 231 women (age 18 to 35 years). Average ioduria of pregnant women at the beginning of gestation (not affected by supplementation) was 127 mg I/l, median 115 mg I/l of urine. Ioduria of non-pregnant women of the control group was 100 mg I/l median 84 mg I/l of urine. Low ioduria (below 100 mg I/l) was found in 40 % of pregnant and 62 % fertile women of the control group. Supplementation resulted in the statistically significant increase of ioduria in the 20th week (average value was 186 mg I/l, median 156 mg I/l); low values had found only 20 % of women. The fourth day after delivery, ioduria was statistically lower than in the 20th week (121 mg I/l, median 99 mg I/l), however, 76 % of women finished with supplementation after the childbirth. Values of ioduria were still higher in supplemented than in non-supplemented women. Conclusions. Iodine intake in the group of pregnant and non-pregnant women was not optimal. Even during the recommended iodine supplementation (100 and 130 mg), 20 % of women had lower values of ioduria. Health education, which first of all involves the risk groups, is therefore highly recommended.

        Key words: iodine, ioduria, pregnancy, pregnant women.