Neonatal thyroid function after administration of IV iodinated contrast agent to 21 pregnant patients.

OBJECTIVE: The objective of our study was to document neonatal thyroid function after in utero exposure to nonionic iodinated contrast material to determine the potential risk of subsequent neonatal hypothyroidism.

MATERIALS AND METHODS: We identified pregnant patients ("maternal patient") who underwent CT with iodinated IV contrast material between February 2000 and October 2006. The specifics of the CT examinations were reviewed including patient age, gestational age of conceptus at time of exposure, type of CT, and type and dose of contrast agent. The neonatal serum thyroid-stimulating hormone (TSH) level obtained from the exposed infant ("neonatal patient") was retrieved from the Minnesota Department of Health.

RESULTS: Twenty-one patients gave us consent to review the requested data concerning their 23 children (two mothers had twins). Mean maternal age at the time of CT was 29 years (range, 19-41 years). Mean gestational age (based on last menstrual period) at the time of CT was 23 weeks (range, 8-37 weeks). Neonatal patients were born at a mean of 38 weeks of gestation (range, 24-41 weeks of gestation). Serum TSH was collected at a mean of 43 hours after delivery (range, 24-70 hours). For all neonatal patients, serum TSH levels were normal. Mean serum TSH was 9.7 muIU/mL (range, 2.2-28.8 muIU/mL). No maternal patient reported thyroid trouble in her child.

CONCLUSION: Based on neonatal TSH measurements in a small number of patients, we found no ill effect of iodinated contrast agents on neonatal thyroid function after in utero exposure.