The Nursing and Midwifery Council (NMC) said it has commissioned the investigations across the Betsi Cadwaladr University Health Board.
Maternity services at Glan Clwyd Hospital in Denbighshire have already come under intense scrutiny.
The health board is also under Welsh government special measures.
The NMC has a legal duty to ensure midwife training is up to scratch.
"We can confirm that the Nursing and Midwifery Council has commissioned an extraordinary review of the delivery of pre-registration midwifery and nursing education and statutory supervision of midwives at Betsi Cadwaladr University Health Board," said a NMC spokesman.
"We are working collaboratively with the Local Supervising Authority, Bangor University and other relevant parties in north Wales as part of this review."
Bangor University is one of the organisations providing recognised NMC degree courses and midwifery qualifications, and places students at health board hospitals.
The college spokesman responded: "We welcome the review and will continue to ensure that our student midwives and nurses have an excellent experience throughout their time at the university."
An official at the Betsi Cadwaladr board said it was "co-operating fully" with the NMC and partners "to make sure this review is carried out".
The Plaid Cymru assembly member Llyr Gruffydd, who has been a vocal campaigner over maternity issues at Glan Clwyd Hospital, described the review as "highly unusual".
"I'm hopeful that this will focus the minds of senior management to ensure there is effective training for midwives as well as a good standard of statutory supervision," he said.
"Those delivering care on the frontline should be allowed to get on with the job rather than face more uncertainty and upheaval."
Mr Gruffydd said he expected the NMC to publish its findings in the autumn.
The way midwives are trained and supervised in north Wales is to face an "extraordinary review" by the profession's watchdog body.