After the mum complained to the HDC, an investigation was conducted.
Today, the findings of that investigation were published. The HDC found no action was taken after a critical complication was revealed during a scan of a pregnant woman's twins.
It also found the oxygen tank to resuscitate the "floppy" baby, after the emergency birth, was not turned on.
As a result the baby was diagnosed with right hemiplegia - a condition that leads to paralysis on one side of the body.
The mum was not told about the failures until her first paediatric appointment.
The DHB and radiologist have been found in breach of the Code of Health and Disability Services Consumers' Rights for the failures.
They have also been ordered to apologise to the distraught family.
Deputy Health and Disability Commissioner Rose Wall said the radiologist's care was "inadequate", and it was critical that he did not undertake any follow-up action after the scan.
She was also critical that the DHB did not have in place appropriate policies to ensure the early involvement of a paediatric consultant for an urgent or emergency birth.
She found that the operating theatre was not prepared for the delivery of twins; initially the oxygen tank on the portable resuscitate was not turned on; and that incorrect storage of a 2.0mm endotracheal tube meant that it was mistakenly used for intubation.
"I consider that at the time of the incident, [the DHB] had several systemic issues.
"This affected the care provided to [the woman] and [twin 1]," Wall said.
In the report, the mum said she and her husband would never forget the events of their twins' birth and hoped staff involved would never forget it and the impact it has had on her family.
The Deputy Commissioner recommended that the radiology service report back to the HDC about the changes it implemented after this event. She also ordered the DHB to commission an external review of its maternity services and taken a number of steps to improve its systems.
In the report, the DHB said: "[We] sincerely apologise for the emotional and physical impact that this series of events has had on [the family]. We have focused our efforts on ensuring that should such an event happen again our systems and processes are robust."