hypothyroidism vary, depending on the severity of the hormone deficiency. at first, you may barely notice the symptoms, such as fatigue and weight gain, or you may simply attribute them to getting older. but as your metabolism continues to slow, you may develop more obvious sign and symptoms

if it doesn't get treated the sign and symptom can become more severe.
constant stimulation of your thyroid gland to release more hormones may lead to an enlarged thyroid ( goiter).

Hypothyroidism