The heartbroken mother of a baby who died of respiratory failure wants answers, saying she took the infant to eight different GP practices -- and insisted he be admitted to hospital -- in the months leading up to his death.

Grieving mum Melanie Harding has laid a complaint with the Health and Disability Commissioner, which the Waikato District Health Board has confirmed it is now responding to.

She claims she was made to feel like an over-anxious mother and was repeatedly sent home with her sick little boy.

Riley Drever was just 4 months old when he died at home from bronchial pneumonia and respiratory arrest in October 2015, made worse by an undetected birth defect which caused a severe stridor (high-pitched breath) and continuous breathing difficulties.

Riley Drever died of respiratory failure after his mother took him to the doctor 16 times over concerns for his breathing. Photo / Supplied.
Riley Drever died of respiratory failure after his mother took him to the doctor 16 times over concerns for his breathing. Photo / Supplied.

Harding claims she took her baby to see eight different practices -- saying it totalled 16 visits -- the last just three days before Riley's death.

But she claims only one referred the baby to Waikato Hospital for suspected laryngomalacia -- where the soft cartilage of the upper larynx collapses inward during inhalation, causing airway obstruction.

"They weren't listening to our concerns," Harding told the Weekend Herald.

"We don't want an apology because that won't bring Riley back. We want people to be accountable."

Harding said she is devastated by her baby's death.

"I cannot remember what he smells like. I can't remember what he looks like without having to look at his photos. I can't remember what his voice sounds like.

"What I do remember is him blue. What I do remember is the high-pitched sound of me pushing air into his lungs. I remember screaming at him to breathe."

Harding lodged an ACC claim for treatment injury over Riley's death. A report to ACC in August last year by retired paediatrician Peter Jankowitz said doctors failed to recognise the degree to which Riley's airway was compromised when he was admitted to Waikato Hospital.

"Had this been recognised, then steps could have been taken to significantly reduce the progression of the laryngomalacia."

At the hospital's emergency department on October 3, Harding and her mother -- a nurse -- insisted Riley be admitted for laryngomalacia after a doctor tried to send the baby home.

Riley was admitted to a ward but two days later he was discharged against Harding and her partner Nick Drever's wishes, despite the baby's oxygen levels falling to 76 per cent -- well below the expected levels of over 95 per cent. Two days after Riley was discharged from Waikato Hospital with a referral for an echocardiogram to check for a heart murmur, Harding took her baby back to a GP.

She said he was prescribed Losec, usually used in infants to treat reflux, and sent home.

More GP visits followed that month until Riley was found on her bed not breathing.

Panicked, Harding rang 111 and began CPR. But when paramedics arrived they pronounced the little boy dead. "I was screaming at him to breathe. I was saying 'Breathe buddy breathe, you need to breathe for Mummy."

In the aftermath Harding blamed herself for her baby's death.

"My most basic role as a human being was to keep my son safe and I failed it."

An autopsy later ruled Riley died of respiratory arrest, secondary to congenital laryngomalacia, and also bronchial pneumonia.

The baby's parents have since complained to the HDC, as well as seeking answers from Waikato Hospital -- including over Harding's treatment while pregnant. Harding had suffered severe polyhydramnios, an uncommon condition in pregnancy where there is too much amniotic fluid in the amniotic sac. Structural malformations of the foetus are known to occur in severe cases.

The office of the HDC confirmed they were assessing the complaint, while the Waikato DHB said it was not in a position to comment while responding to the HDC. Health Minister Jonathan Coleman said he could not comment.