The anterior pituitary may double in size during pregnancy. Seen here is a pituitary completely filling and bulging from the sella in a patient who succumbed to a peripartum hemorrhage. Such a physiologically enlarged pituitary is at risk for ischemic necrosis in such an event because the venous portal system is unable to supply sufficient blood flow to the adenohypophysis. Postpartum pituitary necrosis is known as Sheehan syndrome.