According to clinical experience and relevant guidelines, pregnancy should not be considered until at least six months after iodine 131 treatment. After iodine 131 treatment for Graves’ hyperthyroidism, the iodine 131 containing radiation usually remains in the body for at least one month, and in some patients (with higher doses of iodine 131 or longer retention of iodine 131 in the thyroid gland) for two to three months. Of course, after one month, the amount of residual radiation in the patient’s body is very limited. When the patient’s body is completely free of radiation, the general condition of the body recovers well, and the thyroid function indicators are adjusted to normal levels, the process usually takes six months. At this time it is advisable to consider planning a pregnancy. In addition, there are several phenomena that should be noted after iodine 131 treatment: (1) Early onset of hypothyroidism (low thyroid function) after iodine 131 treatment. Hypothyroidism can also induce menstrual disorders. With low thyroid and hyperthyroidism, the probability of infertility or miscarriage in women is increased. Iodine 131 treatment for hyperthyroidism is a small dose and the probability of radiation damage to the ovaries is not very high (studies are also inconclusive). My personal opinion: Normally the ovaries do not take up iodine and iodine 131 is excreted in the urinary tract. The iodine 131 rays in the bladder may have a short-term effect on the ovaries, but after 6 to 12 months of adjustment and recovery, the probability of radiation-induced abnormalities in the new follicles is low. There should be no effect on pregnancy at this time. (2) For low thyroid, thyroid preparations are needed. (levothyroxine sodium tablets, LT4) for replacement therapy and frequent monitoring to ensure that thyroid blood indicators are within normal reference values before, during and after pregnancy and throughout the postpartum period. The dose of LT4 is safe during pregnancy and should be adjusted according to the pregnancy, maternal weight and changes in thyroid blood parameters. (3) Serum TRAb is likely to be elevated (and high) despite hypothyroidism after iodine 131 therapy. However, this high value of TRAb may be different from the TRAb that induces hyperthyroidism (stimulating antibody TSAb), which is mostly an inhibitory or neutralizing antibody. If this indicator is monitored during pregnancy, it is advisable to inform the pregnant woman not to worry about this indicator.