This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Menstruation, Abnormal Menstruation, Menopausal Physiology and forsight of conception, Subject name: Gynaecology & Obstetrics
All are causes of primary amenorrhea EXCEPT 
Select and explain. 
A. MRKH syndrome, B. Sheehan's syndrome, C. Kallmann's syndrome, D. Turner's syndrome
B: Sheehan's syndrome
Answer: B: Sheehan's syndrome 
Explanation: Sheehan's syndrome Post paum pitutary necrosis. Occurs as a result of ischemic pituitary necrosis due to severe postpaum hemorrhage Presents as failure to lactate or to resume menses (Secondary amenorrhea) Other presentation: genital and axillary hair loss, asthenia and weakness, fine wrinkles around the eyes and lips, signs of premature aging, dry skin, hypopigmentation and other evidence of hypopituitarism.