In the report, Wall criticised the radiologist saying it was his responsibility to review the images carefully, irrespective of what was written on the worksheet.
At 36 weeks of gestation, the woman was rushed to hospital with vaginal bleeding.
The obstetrician reviewed the 19-week scan and ruled out placenta praevia, which had been her initial suspicion.
Instead, the woman's bleeding was diagnosed as a mild abruption, and an induction was started.
The correct diagnosis was not made until the following day, and the woman then underwent an emergency caesarean section which was complicated by excessive blood loss with the placenta low lying and abnormally adherent.
Subsequently, the newborn spent nine days in the neonatal unit. Luckily, both mum and baby survived.
In the report, the radiology service advised that this case had led to a significant improvement in ultrasound accuracy.
Wall recommended that the radiology service and the radiologist provide the woman with an apology. She also advised that the DHB provide a training session for obstetric staff on placenta praevia.