The Effects of Renografin-60 on the Fetal Thyroid

Since many of the dyes used intraamniotically contain a large amount of iodine, it is important to assess what effect this material might have on the fetal thyroid. Twenty-eight patients who underwent amniograms with Renografin-60 were evaluated, as were 25 patients who were not exposed to this material. Serum T4 values and the T3 resin uptake levels were obtained from the cord blood of their progeny. The serum T4 levels were elevated while the T3 resin uptake values were within normal adult limits. There were no fetal thyroid abnormalities found in either group. Also, there was no relationship between the two values and the stage of gestation or time of delivery after Renografin injection. The fate of the Renografin is unknown but the iodine appears to remain organically bound until it is eliminated from the amniotic fluid 2 to 4 days after injection.