What do the narrator's "three coins" represent in the book, Motherhood: A Novel?

The narrator's three coins are symbolic of randomness. Because the narrator feels so internally conflicted, she turns to the coins for answers. However, the more nonsensical the coins' responses to her philosophical and metaphysical questions become, the more frustrated the narrator feels. Ultimately, the coins convey how much of life is the result of chance, happenstance, and luck.