BACKGROUND Thyroid function disorders have often been observed in preterm infants after intravenous administration of iodinated contrast medium. The effect on thyroid function depends on the dosage, but the choice of the contrast medium may be equally important, as there are appreciable pharmacological differences between them.

RESULTS Free thyroxine levels in all study infants ranged from 9.0 to 25.7 pmol/l (days 14–21) and 9.0 to 23.2 pmol/l (days 35–49), and thyroid stimulating hormone levels ranged from 0.13 to 0.26 mU/l (days 14–21) and 0.26 to 11.11 mU/l (days 35–49). These levels were not altered after injection of iopromide.

CONCLUSION The risk of transient hypothyroidism or hyperthyrotropinaemia may be reduced with the use of iopromide compared with other contrast media.