What is the effect of an increase in fetal hemoglobin on the oxygen-hemoglobin dissociation curve?

A Shift to the right
B Shift to the left ✓
C No effect
D Increase in oxygen affinity

Explanation

An increase in fetal hemoglobin shifts the oxygen-hemoglobin dissociation curve to the left, indicating a higher affinity for oxygen.

Source

Guyton and Hall Textbook of Medical Physiology
Hematology Hematology: Hemoglobin and Oxygen Transport Hematology: Hemoglobin and Oxygen Transport Medium MEDICAL Confidence: high