There are some older threads here discussing issues related to UK midwives coming to the US and wanting to practice. Basically, the British model of midwifery training doesn't qualify you for certification as a CNM (certified nurse midwife) in the US. In order to be licensed as a CNM in the US, you have to have completed a Master's (or, nowadays, doctoral) program in nurse midwifery.
Basic RN licensure plus a midwifery program is not considered the same thing. There are non-nurse midwives in the US, but that is an entirely different matter; their ability to practice legally varies greatly from state to state (in some states, they are not legal at all, and some states have no regulations whatsoever, so it's a very grey area legally in those states).
I'm sure that you could find the older threads with the "search" button in the upper right corner of your screen (and some experimentation with search terms
). Best wishes!