Fetal Hb Left Shift ODC — FRCA Primary MCQ
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Correct answer: A — A left-shifted oxygen dissociation curve relative to adult haemoglobin
The best answer is “A left-shifted oxygen dissociation curve relative to adult haemoglobin”. Fetal haemoglobin has a higher oxygen affinity than adult haemoglobin, producing a left shift of its oxygen dissociation curve. This promotes uptake from maternal blood across the placenta. The ductus arteriosus and foramen ovale do not close immediately, and neonates have high oxygen consumption per kilogram.
Reference: RCoA, Primary FRCA Syllabus: https://rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf