The author defends the originality of the work of Dr. Arias-Stella in relation to the histological changes that have been designated in the literature as "Arias-Stella reaction". Also it indicates that the merit of the Peruvian researcher was first described endometrial alterations associated with pregnancy.

The author defends the originality of the work of Dr. Arias-Stella in relation to the histological changes that have been designated in the literature as "Arias-Stella reaction". Also it indicates that the merit of the Peruvian researcher was first described endometrial alterations associated with pregnancy.