Changes in LDL and HDL Subclasses in Normal Pregnancy and Associations with Birth Weight, Birth Length and Head Circumference

Pregnancy is associated with alterations in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclasses, but
the exact pattern of these variations remains controversial. This study investigates longitudinal changes of plasma LDL and
HDL particles distributions during the course of normal pregnancy, as well as associations of maternal LDL and HDL subclasses
distributions before delivery with parameters of newborn size. Blood samples were collected from 41 healthy pregnant women
throughout entire pregnancy, before delivery and 7 weeks postpartum. LDL and HDL subclasses were determined by gradient gel
electrophoresis, while other biochemical parameters were measured by standard laboratory methods. During gestation LDL size
significantly decreased (P < 0.001), due to reduction in relative proportion of LDL I (P < 0.01) and increase of LDL II (P < 0.001) and IIIA (P < 0.05) subclasses. In the same time, HDL size and proportions of HDL 2a particles significantly decreased (P < 0.001), with concomitant increase of HDL 3b and 3c subclasses (P < 0.05). Observed alterations were associated with changes in serum triglyceride levels. Rearrangement in LDL subclasses
distribution during gestation was transient, while postpartum HDL subclasses distribution remained shifted toward smaller
particles. Higher proportion of LDL IVB in maternal plasma before delivery was an independent predictor of smaller birth weights
and lengths, while higher proportions of LDL IVB and HDL 2a subclasses were independent determinants of newborns’ smaller
head circumferences. Routine gestational and prenatal care in otherwise normal pregnancy could be complemented with evaluation
of LDL and HDL particles distribution in order to ensure an adequate size of the newborn.