What metaphors are used in Midwives: A Novel by Chris Bohjalian?

Trust is an underlying metaphor in the narrative. Sibyl Danforth's patients trust her to bring their babies into the world safely and in an environment that will create warm memories for the parents and their families. Sibyl trusts her patients to tell her everything she needs to know in order to determine if the patient is a good candidate for a home birth. On both accounts, Charlotte and Sibyl let each other down.