Why the mother’s blood doesn’t circulate to the foetus in the mother’s womb?

Why the mother’s blood doesn’t circulate to the foetus in the mother’s womb?

The blood in the mother’s blood vessels flow at a high pressure.  If the blood fow to the foetus at this high pressure, the delicate tissue of the foetus get damaged.  To over come this problem, exchange of materials between mother and foetus occur through an organic connection between mother’s uterus and foetus. Useful materials like glucose, oxygen, minerals, hormones and antibodies from mother’s blood diffuse into foetus through placenta. Similarly metabolic wastes like carbon dioxide, nitrogenous wastes from foetus diffuse into mother’s blood through this placenta only.