Lipid and lipoprotein profile in physiological pregnancy

Physiologic pregnancy is associated with a broad series of metabolic adaptations which may also influence the metabolism of lipids and lipoproteins. Although the modification of serum lipids and lipoproteins has been exhaustively investigated during and after pregnancy, the relative changes recorded vary widely among the different studies. A comprehensive lipid and lipoprotein profile was evaluated in 57 women with uncomplicated pregnancies at different gestational ages (20 in the first, 20 in the second, and 17 in the third trimester of pregnancy) and compared to that of 21 non-pregnant women. Conventional lipid parameters, including total cholesterol, high-density lipoprotein cholesterol and triglycerides, were evaluated on the Modular System P. Low-density lipoprotein cholesterol was quantified by the formula of Friedewald, the atherogenic index of plasma was quantified by the formula log (triglycerides/high-density lipoprotein cholesterol), whereas lipoprotein(a) was assayed on the BN II nephelometric analyzer. We observed that all the lipid parameters tested were significantly modified by the gestational age; in particular, women in the second and third trimester displayed significantly increased total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total to high-density lipoprotein cholesterol ratio, lipoprotein(a) and atherogenic index of plasma (third trimester only) when compared to either the control population or the subgroup of women in the first trimester of pregnancy. The value distributions and the relative percentage of women with undesirable or abnormal values according to the current NCEP or AHA/ACC goals were comparable between controls and women in the first trimester. However, when compared with either controls or women in the first trimester, advanced pregnancy was associated with an increased prevalence of undesirable or abnormal values for total cholesterol, low-density lipoprotein cholesterol and triglycerides in the second trimester, and total cholesterol, low-density lipoprotein cholesterol, triglycerides, total to high-density lipoprotein cholesterol ratio and lipoprotein(a) (only from non-pregnant women) in the third trimester. The results of this case-control study demonstrate that physiological pregnancy is associated with a substantial modification of the lipid and lipoprotein metabolism from the second trimester, providing reference ranges for traditional and emerging cardiovascular risk predictors throughout the gestational period.