Is a pregnant mother’s blood kept separate from her fetus’ blood?


I have searched online multiple times to see whether a pregnant mother’s blood and her fetus’ blood are kept separate. I’ve even looked in textbooks, and often it’s implied but never said outright and plainly in those terms.

I’ve looked online, but I’ve not yet found a reputable source that spells it out clearly.

Are a pregnant mother’s blood and her fetus’ blood kept separate? Why or why not?

In: 68

Any references to reputable resources would also be greatly appreciated.

There is a placental blood barrier, yes.

> One of the placenta’s jobs is to make sure blood from the mother and fetus never mixes. The placenta acts as an exchange surface between the mother and the fetus. Nutrients and oxygen are passed over by diffusion only. If the mother’s and fetus’s blood mixed, it could be deadly for both of them. If the mother and the fetus had different blood types, they might both die if their blood mixed.


The blood as a whole never mixes, however some elements in the mother’s bloodstream can cross over it all depends how you are defining blood.

Yes, they’re separate, which is why a baby can have a different blood type than it’s mother. The placenta allows nutrients and antibodies to pass, while keeping the larger blood cells discrete. Unfortunately, drugs and many infectious agents can also pass the placental barrier.

Yes. You know this as well because a mother an child can have different blood types. When you mix incomparable blood types the person involved doesn’t have a good time. Nutrients can transfer between mother and child but not blood itself.