Fetal Blood Circulation

My understanding of Fetal Blood Circulation. The umbilicus vein from the placenta is bringing oxygen rich blood to the fetu’ss liver where deogenated blood from the lower portion of the fetus is mixed (through the Ductus Venosus) and directed to the heart. The blood now 1/2 & 1/2 or decreased O2 runs through the fetus’s heart mixing more with deoxgenated blood running through the lungs and heart (through the Foramen Ovale), and deoxgenated blood from the upper part of the baby (through the Ductus Arteriosus.) Now this decreased blood  is brought back to the placenta.