The low density lipoprotein receptor plays an important role in the uptake of maternal plasma lipoproteins for placental steroid metabolism. Using an RNase protection assay, the expression of low density lipoprotein receptor mRNA was measured in human placentas from pregnancies in the second and third trimester and from pregnancies with intrauterine growth retardation. Pregnancies complicated by intrauterine growth retardation showed a significantly higher expression (1.28), compared with the term and preterm pregnancies (P < 0.05). The increased low density lipoprotein receptor expression in placentas from pregnancies with intrauterine growth retardation could be a compensatory mechanism for the lower circulating low density lipoprotein concentrations in women with intrauterine growth retardation.