What is the theme in A Midwife's Tale: The Life of Martha Ballard, Based on Her Diary, 1785-1812 by Laurel Thatcher Ulrich?

Major themes addressed in the biography, A Midwife's Tale: The Life of Martha Ballard, Based on Her Diary, 1785-1812, include gender roles, the roles of midwives versus physicians, independence, dependence, and interdependence.