Since urinary iodine concentration (UIC) only reflects recent iodine intake and carries limited information on individual existing iodine stores, another biomarker e.g. measurement of serum thyroglobulin concentration, would be useful to gain comprehensive information. In the present study, the purpose of the investigation is to compare UIC, UIC normalized to creatinine concentration and serum thyroglobulin as biomarkers of iodine supply in pregnant women in a geographical region where previously iodine deficiency had been found.