I don’t think the mid-wives need a law. They should form an organization and establish guidelines regarding training and mentoring within this framework. Once the aspiring midwife fulfills these guideposts, then a certificate is awarded. They could require additional classes and training to keep up with the state of the art in order to keep their certificate current.
This is what is done with Professional Engineers in most states.
Our backup midwife in Indiana, for example, was arrested and hauled into court after a pastor and his wife had a stillbirth that she attended. The couple had had three prior stillbirths in the hospital and was hoping that the calmer setting afforded by homebirth might make a difference. Unfortunately it didn't. The prosecution freely admitted that there was no issue with the competence of the midwife and that a hospital would have made no difference to the outcome. In the end I believe she wound up on probation. (The Republican woman who headed the relevant legislative committee was a nurse who had a mindset of "force people to use institutional medicine")
My take is that the free market should hold sway here. If midwives want to form an association and issue certifications, great. But let people choose whom they want, and if they don't value hospitals or value the midwife certifications, so be it.