Up to now, little has been known about iodine intake and the prevalence of iodine deficiency (ID), if any, in Kuwait. Urinary iodine excretion (UIE) and changes in thyroid function during pregnancy were thus evaluated. Urinary iodide level was measured in random urine samples collected from 326 pregnant women at different gestational trimesters. Blood samples were drawn for free T4 (FT4) and TSH level determination. Median UIE levels fall within the normal range during all gestational trimesters i.e. >100 microg/l. However, if the new suggested recommendation for pregnant women <140 microg/l, is applied, median UIE values during trimesters 2 and 3 indicate ID. Mean serum TSH levels increased between trimesters 1 and 3 (p<0.05), whereas serum FT4 decreased between first and second trimesters (p<0.05), and this reduction continued at the third trimester. Furthermore, an increase in TSH levels for subjects with mild and moderate ID (Mi and Mo, respectively) were noticed (p<0.05) during the second trimester. However, FT4 levels dropped in subjects with Mi and Mo ID during the first trimester (p<0.05). In conclusion, these results suggest that 56.8% of pregnant women had median UIE level <145 microg/l, associated with high TSH and low FT4 levels. Data obtained may indicate insufficient iodine intake among pregnant women in Kuwait.