Pregnancy among thyroid cancer survivors: do thyroidectomy and radioactive iodine matter?

Abstract Background Thyroid cancer primarily affects young women and raises concerns about future fertility due to treatments of thyroidectomy and radioactive iodine (RAI) therapy. This study investigated the effects of these treatments on pregnancy probability in young female patients post-diagnosis. Methods A nationwide, population-based study using data from Taiwan’s National Health Insurance Research Database (2000–2017) examined pregnancy likelihood in women ≤45 years with thyroid cancer. The effects of thyroidectomy and RAI therapy on pregnancy were analyzed using logistic regression and Cox proportional-hazards models. Results In a cohort of 10 937 patients with thyroid cancer, 7022 (64.2%) underwent total thyroidectomy, with 718 receiving RAI treatment. The type of thyroidectomy and RAI treatment, even at doses exceeding 120 millicuries, did not reduce the likelihood of pregnancy. Age was identified as the most critical factor influencing pregnancy; women aged >30 years had a significantly lower likelihood of becoming pregnant than younger women did. Other factors associated with a reduced likelihood of pregnancy included comorbidity with diabetes (HR = 0.65, P = .002) and higher socioeconomic status (HR = 0.69, P = .085). Conclusions Thyroidectomy and RAI therapy do not diminish pregnancy probability in young women with thyroid cancer. Age remains a crucial factor, with younger women more likely to conceive. These findings are critical for fertility counseling and treatment planning. Key message What is already known on this subjec? Thyroid cancer primarily affects young women, and its standard treatments, including thyroidectomy and radioactive iodine (RAI) therapy, have raised concerns about their potential impact on fertility. Previous studies have shown that RAI treatment may temporarily affect ovarian function but typically does not have a significant long-term effect on fertility. What this study adds? This nationwide population-based study found that neither total nor partial thyroidectomy, nor RAI treatment, adversely affects the likelihood of pregnancy in young women with thyroid cancer. Age was identified as the most significant factor influencing pregnancy, with younger women having a higher probability of becoming pregnant after treatment. How this study might affect research, practice, or policy? Clinicians should recognize that age, rather than the type of thyroidectomy or RAI treatment, is the most critical factor influencing fertility in young women with thyroid cancer. This insight can guide personalized fertility counseling and treatment planning to optimize outcomes.