Primary hypothyroidism is preventable by supplemental iodine in areas where iodine in the food supply is low. Otherwise, the condition is not preventable.
Being aware of your risk may allow early diagnosis and treatment. Some experts advocate TSH testing in certain high risk groups (e.g., women older than 50 years).
AACE Thyroid Task Force. American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Evaluation and Treatment Of Hyperthyroidism and Hypothyroidism. Endocr Pract. 2002;8 (6).
Ladenson P, Kim M. Thyroid. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2007:chap 244.