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?
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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.
Wikipedia.
If you are looking for sources, search for Rh incompatibility during pregnancy. My kids are old enough that I don’t remember all the ins and outs, but I had to get a shot at 5 months in case the baby had Rh positive blood, so I wouldn’t form antibodies that would harm the fetus. I got another shot after the birth when they checked the baby’s blood type and it was Rh positive.
They don’t always stay completely separate. I mean yes, the blood circulatory system is kept separate enough for the mother and baby to maintain different blood supplies, often different blood types. Certain of the babies cells and DNA do enter the mother’s bloodstream and can remain there for years. Also, the blood can mix during procedures like amniocentesis or vaginal bleeding. There can also be “leaky spots” that can allow exchange. So technically they are two different blood systems, but there can definitely be very small amounts of mingling.
So you know the way the lungs work? Tiny little blood vessels so close to the surface of the lung that blood cells can release carbon dioxide and take in oxygen without they themselves escaping? It’s porous enough to allow the small molecules of oxygen and carbon dioxide to pass through but not porous enough to allow blood cells to pass though.
Well with any pregnancy, the pregnancy will develop a temporary, detachable organ that effectively acts like a lung for the baby called the placenta. It acts like a lung with the mother’s blood being like the atmosphere you breathe in/out, passing oxygen and nutrients to the baby’s blood which flows back to the child via the umbilical cord.
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