THE NATURE OF THE ANEMIA OF PREGNANCY IN THE RAT1

Abstract

Although the anemia of pregnancy in the rat was once thought to be attributed to nutritional deficiencies, some experiments (Mitchell and Miller, 1931; Beard and Myers, 1933; Van Donk, Feldmen and Steenbock, 1934) demonstrated the inadequacy of dietary supplements in the prevention of this condition. The importance of the placenta in the development and maintenance of pregnancy anemia in the rat was demonstrated and the possibility of an endocrine basis for the anemia was suggested (Newcomer, 1947). In none of these experiments was the exact nature of the anemia described, although hemodilution was suggested because erythrocyte changes paralleled hemoglobin changes. In this investigation the nature of absolute and relative changes in some of the blood constituents during pregnancy in the rat was determined. Studies were made on the number of erythrocytes, hemoglobin concentration, hematocrit, whole blood and plasma specific gravities, and blood volume at three stages of pregnancy in rats.