What is the cause of goiter of women?

Many causes.: Overactive (grave's disease) or underactive thyroid, usually secondary to hashimoto's thyroiditis will cause a goiter. In graves', thyroid stimulating antibodies stimulate TSH receptors. In hypothyroidism, the pituitary gland producces more tsh, trying to keep up, but enlarging thyroid tissue at the same time. Benign multinodular goiters, and even solitary nodules can do this. Women more so!