Plasma lipids and cholesterol esterification rate during pregnancy.

Total plasma cholesterol, cholesterol in high-density lipoproteins, unesterified cholesterol, total plasma triglycerides, and plasma cholesterol esterification rate were measured in three groups of subjects, including 176 pregnant, 22 nonpregnant, and 22 postpartum women. Total cholesterol levels showed a 49% increase during pregnancy, reaching a maximum at 33 to 36 weeks. Triglycerides showed a three-fold increase over the levels in nonpregnant women by 37 to 40 weeks' gestation. However, unesterified cholesterol percentage and high-density lipoprotein cholesterol were hardly affected by pregnancy. The hyperlipidemia of pregnancy is accompanied by an increase in the plasma cholesterol esterification rate for the first half of gestation. During the second half of gestation there is little change in the plasma cholesterol esterification rate, in the presence of a continuing increase in plasma lipid levels.