Why did O'Lan kill her newborn daughter? What was the point of that? (The symbolism of it I meant).

O'Lan is unable to feed and care for the child, she thinks her decision to end the baby girl's life is based upon compassion...... she believes a quick death is better than starving. I believe symbolism can be found in the fact that O'lan never would have taken the child's life had she been a male child.