The study described was conducted to evaluate a simple enzymatic method for the study of the cholesterol/phospholipids ratio in erythrocyte membrane (C/PL) in a group of normal pregnant, of hypertensive pregnant, in non-pregnant controls and in cord blood. Subjects consisted of 28 normotensive pregnant women (NT), 14 women with pregnancy induced hypertension (PIH), 10 non-pregnant normotensive women (Non-Preg) and 14 samples obtained from umbilical cord (C) at delivery from normotensive pregnant. Red blood cells were isolated from heparinated blood samples. Lipids were extracted from erythrocytes by isopropanol/chloroform, without preparation of cell ghosts. Cholesterol content was evaluated by cholesterol oxidase and phospholipids were estimated as organic phosphorus in the total lipid extract. We found a significant difference of C/PL between the PIH group and the NT group (1.01, SD 0.11 vs. 0.76, SD 0.10, 95% CI 0.74-0.78; p < 0.001) and the Non-Preg group (0.83, SD 0.11, 95% CI 0.80-0.86; p < 0.001). Cord blood C/PL was significantly elevated with respect to NT (1.25, SD 0.13 vs. 0.76, SD 0.10; p < 0.001). The method was proven to be fast, reliable and of value for the study of the pathophysiology of the alteration of the lipid composition, i.e., the increased cholesterol content, of the red cell membrane found in hypertensive pregnant patients.