Hemingway drew upon Pfeiffer's difficult labor with one child as the basis for his character Catherine's death in A Farewell to Arms.

Pfeiffer's devout Roman Catholic beliefs led to her support of the Nationalists during the Spanish Civil War while Hemingway backed the Republicans.

[3] Her death was attributed to an acute state of shock related to Gregory's arrest and a subsequent phone call from Ernest.

Gregory, later known as Gloria, who had experienced gender identity issues for most of her life,[11] had been arrested for entering the women's restroom in a movie theater.

Years later, after becoming a medical doctor, Gloria interpreted her mother's autopsy report as indicating that she had died due to a pheochromocytoma tumor on one of her adrenal glands.