If thyroid hormones are balanced. what causes thyroid nodules ? i usually take ultrasonography every 6-12 months. and one nodule which is 8 mm stays the same size. (biopsy is not necessary and it is non-cancerous)

Hormonal cycling: The cycling of hormones, especially in women, makes the thyroid go through cyclic increase and decrease in activity and this cycling induces nodules in some people. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine. Wish you good health!