[Early or late cord clamping? A question of optimal time]

Late cord clamping allows a redistribution of placental blood to the fetus within 3 minutes. A sufficient difference in hydrostatic pressure between placenta and fetus is the prerequisite for placental transfusion. Placental transfusion is reduced or diminished if the newborn baby is positioned above the placenta. Blood volume and blood pressure of the fetus are elevated after placental transfusion. The increased blood volume correlates with the effective renal blood flow. There is no difference between cardiovascular parameters 6 hours post partum in infants subjected to early or late clamping of the cord. Nevertheless, erythrocyte volume and oxygen capacity remain high during the first days of life in infants with late cord clamping.

In normal deliveries the cord should be clamped after 1 to 2 minutes. In premature infants, however, placental transfusion is advantageous because the incidence of respiratory distress syndrome is lower with late clamping. If the fetus is hypoxic in utero, redistribution of the blood and placental transfusion takes place already before birth to improve the oxygen supply to the fetal tissue and resuscitatory measures can be undertaken immediately following birth.