Saudi Med J
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To evaluate urinary iodine excretion during the course of pregnancy and postpartum in relation to maternal and neonatal thyroid function parameters in Saudi women living in Jeddah, Kingdom of Saudi Arabia. ⋯ The changes in urinary iodine excretion during the course of pregnancy were documented. The decrease in free thyroxine and free tri-iodothyronine and the increase in reverse tri-iodothyronine concentrations during pregnancy resemble the changes in thyroid hormones seen in non-thyroidal illness. Moreover, the changes in thyrotropin in relation to that of human chorionic gonadotropin support the view that the thyroid gland is not primarily thyrotropin driven in early pregnancy. The results suggest that a more complex control may finally regulate maternal thyroid activity; the pituitary and the chorionic systems both function in an independent way in response to possible different feedback stimuli. This could be a physiological adaptation enabling energy conservation during the high metabolic demands of pregnancy. Finally, the results of the present study point to the need of an increased iodine supply in Saudi pregnant women living in Jeddah, Kingdom of Saudi Arabia to decrease the potential consequences of low iodine intake on maternal thyroid economy.