An investigation into a rise in stillbirths in a health board area has found no "significant issues or concerns".

NHS Forth Valley commissioned reviews into the deaths of 24 stillborn babies after the rate rose higher than the national average in the first half of 2016.

The internal review found in the "vast majority" of cases underlying factors meant the stillbirths could not have been prevented, but in four cases care could have been improved, although the babies may still have been stillborn.

The health board said in a statement: "The internal review did not identify any significant issues or concerns and concluded that, in the vast majority of cases, there were complex underlying factors which meant that the stillbirths sadly could not have been prevented.

"These included fetal abnormalities, genetic conditions, trauma injuries and underlying health issues.

"The internal review also identified a small number of cases (four) where it was felt that the care could have been improved, although this may not necessarily have altered the outcome.

"NHS Forth Valley also commissioned an external review to ensure that all aspects of clinical care were independently reviewed by specialist staff.

"It concluded that care had been delivered to a consistently high standard and that, in many cases, there were significant underlying risk factors."

The external review was carried out by senior staff at NHS Tayside.

BBC Scotland said details released through Freedom of Information revealed the external review found the internal review was probably "overly self-critical" but that in one case where a woman was invited to return home and collect belongings before admission it "probably would have been appropriate" to check the baby's heartbeat with a cardiotocograph machine before she went home.

However, it said it would have been reasonable to delay the test if other measures were "reassuring".

NHS Forth Valley said the external review found "improvements outlined in the internal review for four of the cases were very unlikely to have influenced the outcomes".

Gillian Morton, the health board's head of midwifery, said: "I am pleased that the external review concluded that the quality of care delivered by our local maternity staff was of a consistently high standard.

"I am aware that some of the coverage about the review may have concerned local women and impacted on the morale of local staff.

"I therefore hope that the findings of both reviews will provide some reassurance and restore confidence in our local maternity services.

"Sadly, it is not possible to prevent every stillbirth, however we remain committed to the ongoing delivery of high-quality, safe and effective maternity care.

"We shall also continue to monitor our outcomes, review any cases on an individual basis and act on any learning identified."

The stillbirth rate at the health board fell below national average in the second half of 2016 and remained there in the first half of 2017.