Columbia subject headings:
Midwives--Social aspects--United States--History--20th century.
Midwives--United States--History--20th century.
Harvard subject headings:
Midwives--Social aspects--United States--History--20th century.
Midwives--United States--History--20th century.
Obstetrics--Social aspects--United States--History--20th century.
Princeton subject headings:
Midwives--Social aspects--United States--History--20th century.
Midwives--United States--History--20th century.