The contraindications of 131 iodine thyroid test are children, infants, pregnancy, preparation for pregnancy, breastfeeding, iodine allergy, if you need to do 131 iodine thyroid test, it is recommended to go to regular hospitals and under the guidance of the doctor. 131 iodine is an isotope, which will have a certain effect on the development of the body, so children, infants and young children can not do it. 131 iodine is a radioactive element, which will have a certain effect on the body, so the preparation for pregnancy, pregnant people can not do it to avoid adverse effects on such people. 131 iodine is a radioactive element, which has a certain radiation effect on the body, so people who are preparing for pregnancy or are pregnant should not have it done to avoid adverse effects on such people. 131 iodine may be inhaled by infants and young children through breast milk, which will affect infants and young children, so breastfeeding women should not have it done. 131 iodine itself may cause allergic reactions, so people who are allergic to iodine should not have it done to avoid allergic reactions, which will jeopardize their physical health. However, in clinical practice, the 131 iodine test is seldom used, and the function of the thyroid gland is measured instead of the 131 iodine test. If you are going to have a thyroid 131 iodine test in the near future, avoid eating a lot of seafood and iodine-containing foods, and don’t take thyroid medication or hormones, so as not to affect the test results.