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

Abstract

Background: We tried to evaluate the female fertility and genetic risk to the offspring from the exposure to high-dose (131)I by assessing the pregnancy outcomes and health status of the children of female patients with differentiated thyroid cancer who had received therapeutic doses of (131)I.

Materials and methods: From 1967 to 2002, a total of 1,282 women had been treated with (131)I. 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 (131)I. 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 (131)I 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 (131)I 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.