What qualities or idea might the leap represent?
Two of the leaps signify actual, physical leaps. The first physical leap is during the trapeze accident. The second physical leap is from the tree to the house during the house fire. But symbolically, the leap also represents a bridge, a connection, or a bond. In making a leap from one point to another, a bridge is symbolically signified. In each leap, physical and emotional, Anna (the mother) creates a bridge and a bond between herself and her children or between herself and her future.
Given that part of these symbolic leaps is a connection between past and future, each leap is also a leap of faith. Each is a leap of faith because she can not know for sure what her choices (leaps) will lead to. For example, in the first leap, she intends to save herself and her unborn child. But her unborn child eventually dies stillborn. This is something she could not have foreseen. In the second leap, she marries her second husband. This turned out quite well. She has a happy marriage, learns to read, and has another daughter (the narrator). In the final leap, the narrator notes that "Outside, my mother stood below my dark window and saw clearly that there was no rescue." Even though there seemed to be no rescue, her mother made the emotional and physical leap of faith. Realizing the seeming impossibility of saving her daughter, she risks her own life and leaps anyway.
Each leap symbolizes a connection to another human being. The first leap connects Anna to her unborn child. The second leap connects her to her second husband (and her future daughter with that husband). The last leap connects her to that same daughter. In fact, the daughter's return to care for and read to her mother is also a leap. She literally bridges a geographical gap, returning from the west back to the east to care for her mother. This is her way of returning the favor, of taking a leap for her mother, and rebuilding the bridge:
Since my father's recent death, there is no one to read to her, which is why I returned, in fact, from my failed life where the land is flat. I came home to read to my mother, to read out loud, read long into the dark if I must, to read all night.