According the WHO and ICCIDD statement the increase of neonatal screening TSH value over 5 mU/ liter in more than 3% of the neonatal population in defined geographic area is the signal of the latent iodine deficiency in pregnant mothers, which represents a serious risk for optimal brain development of neonates. The aim of the study was to evaluate the percentage of neonates with screening TSH over 5 mU/ liter in individual regions of Slovakia in 2002. The percentage of the screening TSH above 5 was 4.78 – 4.31 – 3.94 in West, Central, and East Slovak region fulfilling the criterion of the mild iodine deficiency in neonates. Normal iodine status is in whole population. The difference was more obvious in smaller regions (counties). Comparing the map of Slovakia after percentage of neonatal TSH above 5 (data from 2002 year) to the map expressing the frequency of endemic goiter (data from 1953 year), the significant negative correlation has been found. The highest percentage TSH over 5 was in agricultural regions and in regions with heavy PCB environmental pollution. It seems to be possible that high TSH over 5 percentage reflects not only latent iodine deficiency, but it may be the signal of negative influence of various environmental pollutants to the fetal-maternal thyroidal function (nitrites, PCB, etc.).

        Key words: fetal hypothyreosis, screening of congenital hypothyreosis, neonatal TSH, iodine deficit