**1. Introduction**

In spite of the fact that the hyperlipidaemia of pregnancy is usually considered physiological [1-12], all pregnant women develop hypertriglyceridaemia with subsequent formation of small, dense low-density lipoprotein(LDL) particles, both of which are an independent risk factor of coronary heart disease(CHD) [13]. By 3rd trimester most women have a lipid profile which could be considered highly atherogenic in the nonpregnant state [14]. Similarly, animal model studies showed that maternal hypercholesterolaemia during pregnancy even when temporary and limited to pregnancy triggers pathogenic events in the fetal aorta, greatly enhanced atherogenesis later in life[14, 15]. On the other hand, intrauterine growth retardation (IUGR) has been associated with pre-eclampsia [16], as a result of decreased maternal lipid transfer to the fetus secondary to placental abnormalities. IUGR has also been associated with failure of development of hyperlipidaemia during pregnancy with subsequent reduction in maternal lipid reaching the fetus in a normal placenta [17, 18]. Generally, serum lipid and lipoprotein levels in pregnancy are modulated by complex interactions between genetics, medical complications of pregnancy, co-existing medical conditions, and other maternal factors [9, 19]. This underscores the need to take a meticulous and decisive approach in interpreting hyperlipidaemia of pregnancy. In searching for an emergent or new cardiovascular risk factor, concerning lipid and lipoprotein in adult males and nonpregnant women, several lipoprotein ratios or atherogenic indices have been defined[20]. These ratios were found to provide information on risk factors difficult to quantify by routine analyses and could be a better mirror of the metabolic and clinical interactions between lipid fractions[21]. Despite findings of [22] in a registry study of heterozygous familial hypercholesterolaemia(FH) mothers, who observed no significant untoward effect of lipid-lowering drugs during pregnancy, the current trend

© 2012 Mshelia and Kullima, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

is that Statins, classified by FDA as category X, should be avoided in pregnancy[23, 24]. The use of lipid and lipoprotein ratios in interpreting pregnancy associated hyperlipidaemia may provide a balanced hyperlipidaemia not only in normal pregnancy but also in the other modulators of lipid metabolism in pregnancy.
