O can donate to any blood type (universal donor) but can only receive type O in return.
Swing back to Neanderthal times: Neanderthal mother with pure Type O mates with other than O - fetus develops with type A (or B or AB) blood. Mother’s body forms antibodies attacking the A (or B or AB) as foreign substance - first child is born fine, but subsequent O to A (or B or AB) mating results in those same antibodies formed from first pregnancy, attacking fetal A (or B or AB) blood from second pregnancy.
Modern day: Mother requires transfusions to successfully carry subsequent pregnancies with same mate.
Back to neanderthal days: no transfusions avail, then death of mother or death of fetus? with subsequent mating to same mate.
Question to consider: Did crossbreeding with other than O blood types cause extinction of neanderthal female species (death from complications of pregnancy), or cause an inability of cross-bred females to carry to term (inability to provide subsequent generations of neanderthal) because of incompatibility of fetal blood type to maternal blood type?
best regards, blu
I think you may be confusing the blood type with the Rh problem.
If an Rh negative mother has an Rh positive child (I think), the child may be born with a problem and need a replacement transfusion. Then again it may be the reverse. I know my mother was Rh negative and I am Rh positive, but I was the first. I think there are fewer problems if the mother waits 3 or more years between pregnancies.
As someone up there noted, the complication you may be thinking of is due to Rh factor incompatibility; I actually know a family where the mom’s firstborn child wound up slightly developmentally disabled because of blood mingling at birth and the Rh didn’t match.
> Did crossbreeding with other than O blood types cause extinction of neanderthal female species
That’s actually something that didn’t cross my tiny little mind — that Type O might be another legacy of Neandertal. Now that you bring it up, Captain Obvious just smacked me in the back of the head. ;’)