Analysis of the potential for transfer of lipoprotein-cholesterol across the human placenta.

We sought to determine whether evidence exists for the contribution of maternal plasma cholesterol to the fetal plasma cholesterol pool. We found maternal lipoprotein-cholesterol levels at the time of delivery to be significantly higher than those in mixed umbilical cord plasma. The maternal plasma levels of total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol were not correlated to fetal plasma levels of these lipoproteins. There was a weak, but statistically significant, positive correlation between maternal and fetal plasma levels of very low-density lipoprotein (VLDL)-cholesterol. Also, we found a highly significant difference between the levels of HDL-, LDL-, and total cholesterol in umbilical venous and umbilical arterial plasma; venous levels being 7.7-12.8% higher than those in arterial plasma. These data are suggestive that cholesterol derived from maternal plasma can be delivered across the placenta to the fetal compartment in normal pregnancies at term. The contribution of such cholesterol to the fetal plasma cholesterol pool, however, appears to be of minimal quantitative importance in term newborns of women experiencing uncomplicated pregnancies.