Fetal blood and maternal blood meet in the placenta.

However, the bloodstream of the foetus and the mother are always kept separate by a thin membrane, so no blood is exchanged. Instead, materials easily diffuse across the membrane.

The placenta is responsible for:

• transferring nourishment from mother to foetus
• transferring oxygen from mother to foetus
• transferring waste products such as carbon dioxide and urea from foetus to mother.