**9. Malignancy**

The challenge of RAI's late effect is concern developing the risk of malignancy after RAI treatment. Based on multi-center trials, there was no association of any clinical malignancy of RAI for the therapy. [7, 9, 11, 13, 23, 29, 31]. The malignancy is associate with a small risk of pre-existing or coexisting thyroid cancer in patients with toxic nodular goiter. Graves' Disease was not related to cancer development after RAI therapy [23].

### **10. Pregnancy**

Conception should be delayed after six months of the therapy. The same period applies for males to allow irradiated spermatozoa and complete ovarian recovery for patients without undergone gonadal function and thyroid hormone under control [12]. Child-bearing women have no evidence of decreased fertility after received RAI treatment and no adverse outcome on subsequent pregnancies [32]. The incidence of intrauterine growth restriction, neonatal gender, and premature birth did not significantly differ between patients who received RAI therapy and

antithyroid drugs (ATDs). However, a higher abortion rate was found in Graves' Disease patients who received RAI and ATDs [33].

Furthermore**,** patients with intractable Graves' Disease and too high thyroidstimulating receptor antibody who want to pregnant soon should not receive radioiodine therapy to avoid developing fetal or neonatal hyperthyroidism [34]. RAI exposures in the first ten weeks of pregnancy do not affect fetal growth, but after ten weeks, the exposures can affect the growth [35]. Studies reported have no evidence of genetic damage and congenital anomaly, miscarriage, and preterm birth in patients who received RAI with the general population [7, 11, 13, 25, 36–38].
