4.3 Exchange of substances between maternal blood and foetus

Umbilical cord contains two umbilical artery and one umbilical vein.

Umbilical artery transports deoxygenated blood containing nitrogenous waste such as urea from the foetus to the placenta.

At the placenta, the umbilical artery and umbilical vein are surrounded by maternal blood.

Maternal blood has a higher concentration of glucose, amino acids and oxygen than fetal blood.

Glucose, amino acids and oxygen diffuse from maternal blood into fetal blood.

Blood containing higher concentrations of glucose, amino acids and oxygen are transported from the placenta to the foetus via the umbilical vein.