LOW-DENSITY-LIPOPROTEIN PARTICLE-SIZE DECREASES DURING NORMAL-PREGNANCY IN ASSOCIATION WITH TRIGLYCERIDE INCREASES

OBJECTIVE: To characterize the changes in low-density lipoprotein (LDL ) peak particle diameter (diameter of the predominant LDL subclass) in relation to changes in serum triglyceride concentration during succes sive stages of normal gestation and postpartum. METHODS: Nonfasting ve nous blood was obtained longitudinally during and after uncomplicated primiparous pregnancy from 10 nonsmoking women with no history of meta bolic disorders. Plasma LDL diameter was determined by nondenaturing p olyacrylamide gel electrophoresis. Serum concentrations of total chole sterol, triglyceride, apolipoprotein B, apolipoprotein A-I, and LDL-ch olesterol were measured. Gestational changes were analyzed by one-way repeated-measures analysis of variance and the paired multiple compari son Student-Newman-Keuls test. Pearson coefficients were computed for correlation of serum lipids and LDL diameter. Results: Low-density lip oprotein diameter decreased progressively with advancing gestation, ev ident by 16-20 weeks relative to 5-12 weeks. Seven of 10 cases were su bclass pattern B (diameter less than 255 Angstrom or more) by 6-12 wee ks with concentrations of serum triglyceride (r = -.61, P < .0001), ap o B (r = -.66, P < .0001), cholesterol (r = - .53, P < .001), LDL chol esterol (r = -.45, P < .005), and apo A-I (r = -.39, P < .02). CONCLUS ION: Gestational triglyceride increases are accompanied by progressive decreases in LDL diameter in a majority of cases. These changes under go reversal postpartum and therefore are transient. Small, dense LDL p articles have a number of properties capable of altering vascular func tion. However, the consequences of the gestational LDL size decrease f or maternal and fetal metabolism remain unknown. Copyright (C) 1998 by the Society for Gynecologic Investigation.