When do people get their own blood types exactly? Wouldn't it be the same as your mother's at birth, since your two blood streams would be connected up?
question about blood...
- Thread starter visceral_instinct
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WillNever
Valued Senior Member
The blood streams are not connected up. A fetus' circulatory system is separate from that of the mother. The fetal aterioles and venules come very close to the mother's blood supply in the placenta, in units called "cotyledons," where nutrient, waste, and gas exchange occur.
They are two separate blood supplies. Stuff travels between them, but they never normally mix.
Also, blood type is genetically determined by both parents. Mothers and fetuses often have different blood types. If incompatibility occurs, it is due to antibodies from the mother's blood entering fetal circulation, as is what happens in Rh incompatibility after the first pregnancy. This can be avoided by giving the mom RhoGAM.
They are two separate blood supplies. Stuff travels between them, but they never normally mix.
Also, blood type is genetically determined by both parents. Mothers and fetuses often have different blood types. If incompatibility occurs, it is due to antibodies from the mother's blood entering fetal circulation, as is what happens in Rh incompatibility after the first pregnancy. This can be avoided by giving the mom RhoGAM.
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Thanks Will Never 