GESTATION 



989 



TABLE 16.8 



Comparable changes were observed in the 

 blood constituents and plasma volumes of 

 the rat and rabbit during the latter third 

 of gestation. Although there is no increase 

 in the total cell volume, the resultant "phys- 

 iologic" anemia of pregnancy in the rabbit 

 follows the same general pattern as that 

 rei)orted in the human being (Horger and 

 Zarrow, 1957). 



A significant decrease in the erythrocyte 

 number, hemoglobin concentration, and he- 

 matocrit, and an increase in the blood vol- 

 ume have been noted in the rat during 

 pregnancy (Table 16.8). However, the in- 

 crease in blood volume is correlated with 

 an increase in body weight and the ratio 

 of blood volume to body weight remains un- 

 changed (Bond, 1948). Calculation of the 

 total number of erythrocytes and grams of 

 hemoglobin actually showed an increase in 

 these constituents during gestation, indicat- 

 ing that the anemia of pregnancy in the 

 rat is due to a hemodilution in which 

 the blood volume increases proportionately 

 faster than the number of erythrocytes. 



Comparable results were also reported in 

 the rabbit (Zarrow and Zarrow, 1953). A 

 marked drop in the relative number of 

 circulating erythrocytes and percentage of 

 hemoglobin is seen invariably towards the 

 end of gestation (Fig. 16.23). A marked 



Fig. 16.23. Changes in the relative number of 

 circulating erythrocytes, reticulocytes, percent- 

 age of hemoglobin, hematocrit, and nonprotein 

 nitrogen of the blood of the rabbit during preg- 

 nancy and after parturition. (From M. X. Zarrow 

 and I. G. Zarrow, Endocrinology, 52, 424, 1953.) 



