Urinary iodine excretion and thyroid function in pregnant women of Bydgoszcz District prior to and after the introduction of iodized salt

INTRODUCTION: Before the introduction of the kitchen iodized salt in 1997 Poland was an area of mild and moderate iodine deficiency. AIM: The aim of the study was to determine the degree of iodine deficiency and thyroid function in pregnant women prior to and after the introduction of iodized salt. MATERIAL AND METHODS: Iodine urinary excretion and serum levels of TSH, fT3 and fT4 were determined in pregnant women divided into the two groups--with and without iodine supplementation. RESULTS: Before the introduction of the kitchen iodized salt iodine urinary excretion in pregnant women was 70.46 +/- 43.99 micrograms/l. The introduction of kitchen iodized salt increased iodine urinary excretion to 92.23 +/- 42.14 micrograms/l (p < 0.01). In pregnant women with iodine supplementation serum levels of TSH and fT3 were reduced. CONCLUSIONS: 1. There was a mild iodine deficiency in pregnant women before the introduction of the kitchen iodized salt programme. 2. The kitchen iodized salt increased iodine urinary excretion rates, 3. Reduced levels of serum TSH and fT3 after the introduction of iodized salt indicate diminished thyroid stimulation in pregnant women with higher iodine intake.