Increases in serum lipids during pregnancy in type 1 diabetic women with nephropathy

During pregnancy women with Type 1 diabetes do not differ from normal women with respect to pregnancy-associated changes in serum lipid levels. However influence of diabetic nephropathy on lipoprotein metabolism in pregnancy has not been described previously. Changes in lipids were compared during and after pregnancy in 10 Type 1 diabetic women without macroproteinuria as well as in 5 diabetic women with macroproteinuria due to diabetic nephropathy. In the pregnant women with macroproteinuria, compared to the diabetic women without macroproteinuria, we observed both significantly higher total and percent increases in serum levels of total cholesterol (97% versus 48%) and of LDL-cholesterol (137% versus 50%), which had risen progressively throughout gestation. The percent increases in serum triglycerides (115% versus 128%) were similar in both patient groups. Metabolic control was improved during pregnancy in both groups of women. Renal function remained normal throughout pregnancy in the diabetic women without nephropathy and worsened during pregnancy in the proteinuric women. The mean protein excretion showed a physiological rise from 0.107 +/- 0.040 g 24 h-1 before pregnancy to 0.336 +/- 0.234 g 24 h-1 in the third trimester in the nonproteinuric women, and an increase from 2.2 +/- 1.0 to 7.1 +/- 1.7 g 24 h-1 during the same period in the women with macroproteinuria. Therefore, it is concluded that the greater increase in serum lipid levels during pregnancy in the women with pre-existing diabetic nephropathy can mainly be explained by the concomitant increase in proteinuria associated with development of the nephrotic syndrome in these patients.