Which of the following is not a cause of primary amenorrhea?

Sheehan's syndrome is associated with secondary amenorrhea and not primary amenorrhea all the other options are examples of primary amenorrhea, hence sheehan's syndrome is the best answer. Sheehan's syndrome: Is postpaum pituitary apoplex The hyperplastic enlargement of the pituitary during pregnancy increases the risk for hemorrhage and infarction (ischemic necrosis of most of the anterior pituitary) This leads to secondary amenorrhea, failure of lactation after delivery Ref: Harrison's Principles of Internal Medicine, 16th Edition, Page 2078; Shaw's Textbook of Gynaecology, 14th Edition, Pages 259-60