Health outcomes of children fathered by patients treated with radioiodine for thyroid cancer

Context and objectives Radiation is known to be mutagenic. The present study analyses birth outcomes and the health of offspring from men previously exposed to ¹³¹I treatment for thyroid carcinoma. Methods Data on 493 pregnancies (356 from 173 untreated fathers, 23 from 17 patients who have undergone surgery alone and 114 from 63 fathers who received ¹³¹I) were obtained by interviewing male patients treated for thyroid carcinoma who had not received significant external radiation to the testes. Among these pregnancies, 73 were conceived from fathers who had received more than 370 MBq. Results The mean activity for the 114 pregnancies fathered by 63 patients was 3993 MBq leading to an estimated radiation dose of 9·2 cGy to the testes (MIRD committee coefficient). No significant differences between untreated and treated fathers were found for any adverse outcome. Conclusion There was no evidence that exposure to radioiodine affects the outcome of subsequent pregnancies and offspring, whatever the event considered. As our study is underpowered, the question of whether testicular irradiation, fractionated or not, is linked to impaired fertility or consequences on offspring remains to be established.