It must be a doctor able to deliver babies at the hospital closest to the client. That's either an OB or a family doc, though I'm not sure there are ANY family docs still delivering babies in this state.
The Louisiana laws and rules can be read at
www.lsbme.org.
Also, since the backup is mandated in the Midwifery Act, it would take an act of congress (literally) to change this part of our midwifery laws. The board members have been very clear on that.