Why doesn't the blood rush to a babies head when he flips into the head down position?

Well, In the case of adult/child we're used to oxygen, and the only reason we know the blood rushes to our head is because of all the oxygen in it going to our head at the same time. Babies inutero however don't depend on oxygen, so they don't know. It does rush to their head, but it doesn't make a difference because there is no oxygen in it.