It is best to avoid having your thyroid function checked during your menstrual period, as the results will be inaccurate. Thyroid function is determined by the level of hormones in the body. The thyroid function test can be performed 5-7 days after the end of the menstrual period. It is necessary to draw blood for the thyroid function test, but it is not necessary to fast. In case of abnormal thyroid function, you need to have a test to determine whether it is hypothyroidism or hyperthyroidism and choose the appropriate treatment. If it is hyperthyroidism, you can have surgery, medication or radioactive iodine treatment. In case of hypothyroidism, thyroid preparations can be chosen for treatment. During treatment, attention should be paid to diet, less stimulating food and a light diet.