Fetal haemoglobin has a higher affinity for oxygen than adult haemoglobin (the fetus's blood is better at absorbing oxygen than its mother's blood). This is really important because the fetus gets oxygen from its mother's blood across the placenta.
By the time the mother's blood reaches the placenta, its oxygen saturation has decreased because some has been used up by the mother's body. The placenta has a low pO,, so adult oxyhaemoglobin will unload its oxygen
what does it mean if fetes haemoglobin has a higher affinity for oxygen
fetal haemoglobin takes up oxygen in lower pO2 that adult
dissociation curve for adult haemoglobin and fatal haemoglobin
