Cwm Taf maternity: Review of midwife report handling
Cwm Taf Morgannwg health board is reviewing how an internal report by a consultant midwife highlighting maternity problems was dealt with.
Its chief executive, Allison Williams, said it was "not handled in line with recognised and usual" processes.
The report's existence was only discovered when an independent review team went in late last year.
It found services "dysfunctional" and the health board heard "significant work remains to be done".
It is a month since the publication of the damning report into maternity services at the Royal Glamorgan Hospital near Llantrisant and Prince Charles Hospital in Merthyr Tydfil.
The review by two royal colleges heard that mothers who came forward with concerns were ignored or made to feel worthless.
In a board meeting in Abercynon, the chief executive confirmed that an external review had started to look at the handling of an internal report by a consultant midwife.
The report highlighted many safety concerns last September but was not acted upon.
The royal colleges review said it was "dismayed" at the lack of action, "thereby continuing to expose women to unacceptable risks".
Ms Williams said: "The needs of women and their families must be central to everything that is done to address the failings in maternity services."
She also revealed since the end of April, 39 women or their families have contacted the health board via its dedicated contact line or email asking for advice or for their care to be reviewed.
Health Minister Vaughan Gething put Cwm Taf maternity services into special measures following the review and appointed the head of an independent panel to oversee improvements.
On Wednesday, Rhondda Cynon Taf Council leader, Andrew Morgan, called on Ms Williams to consider her future in light of the failings.
The health board - which handles 3,700 births a year - said it accepted all of the findings and "apologised unreservedly" for the distress caused to families affected, adding that it was "absolutely committed to putting right the very serious concerns identified by the review team."
The independent panel will pick up the review of 43 cases between 2016 and September 2018, including eight stillbirths and four neonatal deaths.
It is expected to look back at another six years of cases and potentially another two years beyond that.
It has already emerged that there were 67 stillbirths that will be examined.