Conception after iodine-131 therapy for differentiated thyroid cancer

Area of Science:

• Endocrinology
• Reproductive Health
• Oncology

Background:

• Differentiated thyroid cancer is often treated with radioactive iodine (131I).
• The safety of pregnancy post-131I therapy requires further investigation.
• Assessing risks associated with 131I exposure during pregnancy is crucial.

Purpose of the Study:

• To evaluate the risk of congenital disorders in pregnancies following 131I therapy for differentiated thyroid cancer.
• To determine if the timing of conception relative to 131I therapy impacts pregnancy outcomes.

Main Methods:

• Retrospective review of medical histories of 26 women with differentiated thyroid cancer.
• Analysis of 39 pregnancies occurring after 131I therapy.
• Categorization of pregnancies based on timing relative to 131I therapy (within first year vs. after first year).

Main Results:

• Six pregnancies within the first year post-131I therapy resulted in three anomalies: Trisomy 18, aplastic anemia, and hip dysplasia.
• Thirty-three pregnancies after the first year post-131I therapy had two spontaneous abortions and one case of ureteral stenosis.
• Congenital disorders were observed in 3 of 6 pregnancies within the first year post-therapy.

Conclusions:

• While not definitively confirmed, the data suggest a potential increased risk for congenital disorders in pregnancies within the first year after 131I therapy.
• Pregnancy avoidance for at least one year post-131I therapy is recommended.
• Further research is needed to establish a causal link between 131I therapy and observed anomalies.