Organ transplants require that the donor have a blood type that is compatible with the recipient.
Why is that not a requirement when you are actually growing the organs themselves during a surrogate pregnancy?
Thanks in advance!
In: Biology
Women’s bodies are already ‘designed’ to carry children with mismatching blood types.
The way pregnancy works already accounts for the issue, because even a natural pregnancy will have a mismatch; unless the baby has the same blood type, either the women’s blood wouldn’t work in the baby or vice versa.
The blood of the baby and the mother never actually interact. The placenta acts as a filter that facilitates the transfer of nutrients/oxygen from the mother and carbon dioxide/waste from the fetus, but the blood of each that transports the nutrients/waste never comes in contact with each other. Organs, in contrast, are directly in contact with the host blood supply, so incompatibility issues are severe.
As a result, babies and mothers can have different blood types – this is fairly common in normal pregnancies (I myself have a different blood type than my mother did).
There are _some_ diseases that can occur if the mothers have different blood types than their babies (particularly Rh factors) but they are uncommon.
it’s a non-starter, because you have no idea what the blood type of your baby will be when you are choosing a surrogate unless the bio mother and father are both type O. Otherwise it’s at best a coin flip.
Actually, it does. Whether a surrogacy or natural pregnancy, if the mother’s blood type is negative and the baby’s blood type is positive, there can be an immune response against it, especially in a second pregnancy. There’s a medication available to take that prevents the immune response, though.
If the surrogate has Rh negative blood that is a concern but they can test beforehand to see if she has antibodies from a previous pregnancy or miscarriage. Doctors can easily give her Rhogam near the end of pregnancy and after delivery to prevent complications.
The same reason they don’t matter when people have babies without the surrogate, parents’ blood doesn’t mix, and nor does the blood of the foetus with the mother’s. Placenta exchanges nutrients, oxygen/CO2 and waste products with the mother’s circulatory system, but blood cells never cross that barrier.
It’s not that it doesn’t matter, but it doesn’t matter as much.
The placenta is a filter between mother and child, so there is very little blood or tissue Mix between the two. There still can be issues relating to blood typing. Baby’s blood cells are detectable in the mother’s blood, that’s how current generation genetic tests on pre-term fetus work. So if there is a mismatch between mother and child it can cause illness or stress for either mother or child, but rarely is this stress a fatal issue.
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