Oxidation and Synthesis of Fatty Acids in Human and Rat Placental and Fetal Tissues

The rat fetus (day 21 of pregnancy) covers its fatty acid (FA) demands at equal amounts both by maternal-fetal FA transfer and fetal FA synthesis. At the end of the first trimester the human fetal FA synthesis is too small to cover the fetal FA requirements. Therefore, the transfer of FA from the mother to the fetus seems to be the predominant source of fetal FA. The FA oxidation is greater than the FA synthesis in human and rat placenta as well as in the human fetus at the end of the first trimester, whereas the rat fetus (day 21 of pregnancy) oxidizes and synthesizes FA at equal amounts.