Conception after Iodine-131 Therapy for Differentiated Thyroid Cancer

We reviewed the medical history of 26 women with differentiated thyroid cancer who became pregnant after receiving therapeutic doses of radioactive iodine (¹³¹I) in order to document the possibility of a greater risk for disorders in these pregnancies. There were a total of 39 pregnancies, 6 of which occurred during the first year after therapy. In 3 cases the following anomalies were encountered: a male suffering Trisomy 18 (Edward's syndrome), a female with constitutional aplastic anemia, and a male with a congenital hip dysplasia. Of the 33 pregnancies that occurred after the first year post-therapy, there were 2 spontaneous abortions and a male effected by ureteral stenosis. Based on these data, although it cannot be confirmed that these congenital disorders are due to the ¹³¹I therapy, we recommend that pregnancy be avoided for the first year after therapy.