Thyroid function in very low birthweight infants after intravenous administration of the iodinated contrast medium iopromide

Background-Thyroid function disorders have often been observed in preterm i nfants after intravenous administration of iodinated contrast medium. The e ffect on thyroid function depends on the dosage, but the choice of the cont rast medium may be equally important, as there are appreciable pharmacologi cal differences between them. Method-Thyroid function was analysed in 20 very low birthweight infants of gestational age less than 30 weeks after injection of iopromide, a monomeri c nonionic iodinated contrast medium. Levels of free thyroxine and thyroid stimulating hormone were compared with those in 26 control infants. Results-Free thyroxine levels in all study infants ranged from 9.0 to 25.7 pmol/1 (days 14-21) and 9.0 to 23.2 pmol/1 (days 35-49), and thyroid stimul ating hormone levels ranged from 0.13 to 0.26 mU/1 (days 14-21) and 0.26 to 11.11 mU/1 (days 35-49). These levels were not altered after injection of iopromide. Conclusion-The risk of transient hypothyroidism or hyperthyrotropinaemia ma y be reduced with the use of iopromide compared with other contrast media.