Alterations of serum lipid levels and their biological relevances during and after pregnancy

In normal pregnancy, all women displayed a significant elevation of serum triglyceride (TG), total cholesterol (TC), low density cholesterol (LDL-C) and high density cholesterol (HDL-C) during parturition. To study the quantitative changes in serum levels of lipids and their biological relevances during and after pregnancy, blood samples were collected from 62 normally pregnant women throughout gestation and 6 to 12 weeks postpartum. Compared with 184 nonpregnant control subjects, TG, TC, LDL-C and HDL-C were significantly elevated during the second and third trimesters of pregnancy but dropped sharply after pregnancy. To further understand the effect of pregnancy on other metabolic parameters, we compared the relative levels of apolipoproteins such as apolipoprotein A-I (apoA-I) and apolipoprotein B (apoB), lipoprotein (a) (Lp(a)) and blood sugar during and after pregnancy. We found that apoB concentration progressively increased with advancing gestation, while the levels of apoA-I, Lp(a) and blood sugar were independent of gestation process. The physiological significance of hyperlipidemia during pregnancy is also discussed in this study.