Cwm Taf thorough maternity inquiry 'essential'
The senior health official reviewing maternity services for Cwm Taf health board said they were looking at 43 cases where babies died or the mother had complications.
Prof Angela Hopkins, interim director of nursing, said it did not mean anything had gone wrong but they wanted to look deeper in case lessons could be learned.
Twenty stillbirths and six cases of babies dying shortly after birth are being investigated by a health board.
The Welsh Government is monitoring the situation and said it was looking at ways it could provide support to strengthen maternity services, both in the immediate and longer term.
The review was triggered after health board officials noticed a fall in the number of serious untoward incidents (SUI) being reported.
But Prof Hopkins said it was about processes not a question of anyone covering anything up.