High-dose radioiodine treatment for differentiated thyroid carcinoma is not associated with change in female fertility or any genetic risk to the offspring

Background: We tried to evaluate the female fertility and genetic risk to the offspring from the exposure to high-dose I-131 by assessing the pregnancy outcomes and health status of the children of female patients with differentiated thyroid cancer who had received therapeutic doses of I-131. Materials and Methods: From 1967 to 2002, a total of 1,282 women had been treated with I-131. Of these patients, 692 (54%) were in the reproductive age group (18-45 years). Forty women had a total of 50 pregnancies after high-dose I-131. Age at presentation ranged from 16 to 36 years (mean, 23 4 years). Histopathology was papillary thyroid cancer in 32 cases and follicular thyroid cancer in 8 cases. Results: Single high-dose therapy was given in 30 cases, 2 doses were given in 7 cases, 3 doses were given in 2 cases, and four doses were given in 1 case in which lung metastases had occurred. In 37 patients (92%), disease was successfully ablated before pregnancy. Ovarian absorbed-radiation dose calculated by the MIRD method ranged from 3.5 to 60 cGy (mean, 12 +/- 11 cGy). The interval between I-131 therapy and pregnancy varied from 7 to 120 months (37.4 +/- 28.2 months). Three spontaneous abortions occurred in 2 women. Forty-seven babies (20 females and 27 males) were born. Forty-four babies were healthy with normal birth weight and normal developmental milestones. Twenty women delivered their first baby after I-131 therapy. The youngest child in our series is 11 months of age, and the oldest is 8.5 years of age. Conclusions: Female fertility is not affected by high-dose radioiodine treatment, and the therapy does not appear to be associated with any genetic risks to the offspring. (c) 2005 Elsevier Inc.