I wonder if you could do it around visiting hours and then it would be a private service not done with the hospital but the mothers / fathers arranging before the birth... as a start... maybe advertise via independent midwifes, or home birth support groups so that when you have something started you could then go to the hospital with examples etc of what you've done, how you've done it and the outcome.

I could see the hospitals having a problem with the "door knocking" approach, interrupting new parents etc