THE INTRAVASCULAR MASS OF ALBUMIN DURING HUMAN-PREGNANCY - A SERIAL STUDY IN NORMAL AND DIABETIC WOMEN

Objective To quantify the changes in serum albumin during human pregnancy. Design Longitudinal prospective study. Setting Before conception and antenatal clinic. Subjects Sixty-nine normal women and 23 women with Type 1 diabetes. Interventions Administration of Evans' blue dye and collection of serum samples. Main outcome measures Albumin concentration, plasma volume and intravascular mass of albumin Results In normal subjects serum albumin concentration showed a significant decrease of 1.9 (95% CI 1.0 to 2.9) g/l by 7 weeks gestation with a further 8.2 (95 % CI 7.5 to 8.9) g/l decrease by 36 weeks gestation, an overall change of 22%. Plasma volume first increased significantly by 190 (95% CI 105 to 275) ml between 7 and 12 weeks, with a further increase of 1003 (95% CI 871 to 1135) ml between 12 and 36 weeks of pregnancy, a change of 53%. The intravascular mass of albumin showed no change between non-pregnant, 7 and 12 week values but there was a significant rise of 19.5 (95% CI 15.1 to 23.9) g between 12 and 28 weeks of gestation, an overall increase of 19%. Diabetic subjects showed similar changes. Conclusions Rather than simply reflecting plasma volume dilution, the changes in serum albumin imply alterations in albumin metabolism during pregnancy.