The New York Times looks at the prosecution of midwives in Indiana, where only doctors and nurses can legally assist births. I believe the same may hold true in Maryland, where we used a licensed midwife-nurse for our daughter’s birth.
Midwifery certainly predates any law governing the practice or the modern-day practice of hospital deliveries. This doctor-hospital thing is a fairly recent practice, while midwives have been birthing babies for millennia.