You might get more information looking through the boards for certified nurse-midwives: Certified Nurse-Midwives (CNM)
Also the American College of Nurse-Midwives is another place to look: American College of Nurse-Midwives
Kind of a complicated question - Certified Nurse Midwife (CNM) is the credential. And they may be licensed as advanced practice nurses or as nurse practitioners or as midwives... depends on the state. Just a technicality there.
You don't have to become a women's health nurse practitioner to become a nurse-midwife. There's quite a bit of overlap (as I understand it) in the training of the two specialties.
I like the Journal of Midwifery and Women's Health - Journal of Midwifery & Women’s Health - Wiley Online Library
I've been a subscriber for years - great way to learn more about the profession.