Endocrine Abstracts

Background: Pregnancy outcome after radioiodine treatment for differentiated thyroid carcinoma (DTC) is debated. Some studies found a 23% infertility rate after radioiodine treatment. On the other hand, postoperative radioiodine therapy for DTC had no significant effect on spontaneous abortion, premature, stillbirth and congenital malformation.

Aim: To access pregnancy outcome in a series of women with DTC treated with radioiodine postoperatively.

Subjects and methods: Seven women with pregnancies after radioiodine treatment for DTC were retrospectively reviewed. Average age at DTC diagnosis was 24 ± 6.5 years.

Results: Median maximum tumor diameter at diagnosis was 1.5 cm (25 ^th percentile: 1 cm, 75 ^th percentile: 2 cm). Pathology revealed one papillary thyroid carcinoma, 4 follicular variant of papillary thyroid carcinomas and 2 diffuse sclerosing variant of papillary thyroid carcinomas. Thyroid carcinomas were multifocal in 4 cases. Mean radioiodine dose administered was 164.4 ± 57.7 mCi ¹³¹I. Median interval between last radioiodine dose and baby delivery was 57 months (25 ^th percentile: 23.25 months and 75 ^th percentile: 110 months). One patients had 2 spontaneous abortions before successful pregnancy. All babies are in good health.

Conclusions: Pregnancy outcome is favorable in young patients treated with radioiodine for differentiated thyroid carcinomas when conception occurs at least 12 months after treatment.