994 



SPERM, OVA, AND PREGNANCY 



dropped 13 per cent and the albumin 26 

 per cent. The various globulin fractions 

 showed a rise except for the y-globulin 

 (Mack, 1955). As a result of these changes, 

 the albumin-globulin ratio declines 

 throughout pregnancy and shows the well 

 known reversal (Fig. 16.27) and recovery 

 to normal by 6 weeks postpartum. 



Although it is obvious that the albumin 

 fraction is important in maintaining the 



Non- First Second Third Delivery 5-6 6-12 



pregnant trimester days weeks 



Dostpartum 



Fig. 16.27. Progressive decreu.se in the albumin- 

 globulin ratio of the plasma during pregnancy in 

 women. (From H. C. Mack, The Plasma Proteins 

 in Pregnancy, Charles C Thomas, Springfield, 111.. 

 1955.) 



E 150 



100 



2nd 



Z'<^ POST 

 PARTUM 



Fig. 16.28. Changes in the glomerular filtration 

 rate throughout pregnancy in the woman. (From 

 W. J. Dignam, P. Titus and N. S. Assali, Proc. 

 Soc. Exper. Biol. & Med., 97, 512, 1958.) 



blood fluid compartment, the changed 

 albumin-globulin ratio cannot solely ac- 

 count for the retention of water and edema 

 present in pregnancy. Although it has been 

 argued that the hypoalbuminemia through 

 diminished colloid osmotic pressure is the 

 cause of water retention in the tissues, 

 the occurrence of the postpartum diuresis at 

 the time when the albumin is lowest would 

 tend to indicate some other mechanism 

 (Dieckmann and Wegner, 1934a-d). Ad- 

 ditional mechanisms, such as changes in the 

 hormone level, especially the sex steroids 

 and adrenal corticoids, may be responsible. 



IX. Renal Function 



Studies on renal function during preg- 

 nancy have resulted in contradictory re- 

 ports. The earlier investigations failed to 

 show any effect of pregnancy on renal func- 

 tion (Chesley and Chesley, 1941; Welsh, 

 Wellen and Taylor, 1942; Dill, Isenhour, 

 Cadden and Schaffer, 1942) , whereas recent 

 studies indicate a marked change in renal 

 function during gestation (Bucht, 1951; 

 Dignam, Titus and Assali, 1958). Part of 

 the explanation for the divergent results 

 could be the type of patient studied, the 

 periods when studied, and the types of 

 controls. Dignam, Titus and Assali studied 

 both the renal plasma flow and glomerular 

 filtration rate in various patients through- 

 out gestation and immediately following 

 l^arturition. Care was taken to select in- 

 dividuals without any history of cardio- 

 vascular or renal disease. Both the renal 

 plasma flow and the glomerular filtration 

 rate (Fig. 16.28) were increased through- 

 out gestation. The initial rise was ex- 

 tremely marked during the 1st and 2nd 

 trimesters of pregnancy. A slight rise was 

 noted during the 3rd trimester and a re- 

 turn to normal by 6 to 8 weeks postpartum. 



Recently, de Alvarez (1958) reported a 

 50 to 60 per cent rise in the glomerular 

 filtration rate and a 60 per cent rise in the 

 renal plasma flow during the 1st trimester 

 of pregnancy in the human being. This is 

 in agreement with the findings of Dignam, 

 Titus and Assali (1958). However, de Al- 

 varez reported, in addition, a progressive 

 decline in both the glomerular filtration 

 rate and renal plasma flow during the 2nd 

 and 3rd trimesters. The filtration factor 



