Faced with the worst cot death rate in the developed world, the NZ Government set a national target for reduction in 2017 and ramped up measures to prevent deaths. Three years on, is the Government on track? No one really knows.
Healthcare workers who are trying to reduce the number of cot deaths in New Zealand are "flying blind" because of a huge backlog of investigations.
The delay in getting coroners' reports on baby deaths - often three years or longer - means experts are unable to tell whether interventions are working.
That is a concern for the sector because the most recent available data on sudden unexplained death in infancy (SUDI) showed that rates were plateauing after several years of decreases. Among the Pacific population, rates were rising.
"At the simplest level, we are running in the dark," said Professor Ed Mitchell, an infant death researcher at the University of Auckland and member of an expert advisory group on SUDI.
Mitchell said there was always a delay with SUDI cases because of the complexity of the investigations, but he could not recall a time when they were so far behind.
"Effectively, we are two and a half years behind what's actually happening. So it's really difficult to know whether the [initiatives] are working or not working."
New Zealand has one of the highest SUDI rates in the developed world. More than half of the babies are accidentally suffocated by parents while sleeping in the same bed.
Māori and Pacific babies are more likely to die because of high smoking rates in pregnancy (which can create breathing difficulties for their children) and cultural customs of bed-sharing.
In 2017, the National-led Government launched a national prevention campaign and set a target of reducing the SUDI rate from 0.7 per cent per 1000 live births to 0.1 per cent by 2025.
In 2017 - the most recent statistics available - there were 48 SUDI deaths, or 0.8 deaths per 1000 births. Of that total, 26 babies were Māori and 12 babies were Pasifika.
Mitchell said the Government's goal of reducing deaths to just six a year was always going to be ambitious.
"To achieve it, every pregnant mother would have to stop smoking. Both you and I know that's not going to happen in five years."
But without up-to-date data it was difficult to know whether health messages and resources were reaching the families who needed them - and if they were, why they were not being adopted.
Ministry of Justice data shows that the average time to close a coronial case is currently 479 days. Investigations into baby deaths can take longer because underlying conditions and other potential causes must be ruled out before they can be confirmed as a SUDI.
Chief Coroner Judge Deborah Marshall said the main driver of the large backlog of cases was the highest-ever caseload in the 2018/19 year - 200 more than the previous year.
Eight extra relief coroners were appointed by the Attorney-General earlier this year, and have been inducted over the last few months. But at the same time, six long-serving coroners had resigned or retired - five of whom had been replaced.
By law, there is a cap of 20 coroners. Once the vacant roles are filled, there will be 18 full-time coroners and eight relief coroners.
"As the relief coroners and newly-appointed fulltime coroners settle into their roles, I expect that backlog will reduce and the current lengthy wait times will improve," Marshall said.
Selah Hart, CEO of the national service for SUDI prevention Hāpai Te Hauora, said the Ministry of Health provided provisional, monthly data on SUDI deaths every month but this was not robust enough to base prevention measures on.
She would not say what that data showed, but hinted that SUDI rates were not falling: "We have much more that we need to do, especially for our Māori babies".
The national prevention programme established in 2017 funds DHBs to educate families and supply them with safe sleeping devices. Around $5m is spent on education and providing 8500 pepi pods, wahakura and cots a year to at-risk families.
Hart said the delays in getting robust findings was "stalling" Hāpai Te Hauora's ability to "drive out key pieces of work" in areas with high rates of SUDI. Her team has met with the Chief Coroner to discuss the problem.
"It's not anyone's wrongdoing," Hart said. "It's just that there isn't the capacity to meet demand of investigating every single SUDI death in a timely manner that isn't having us three years behind."
The most recent SUDI cases highlight that simply providing health advice to families is not always enough.
In a report released in June, a coroner said that an Auckland family had spoken with health professionals about bed-sharing with their two month-old boy and had been following the advice carefully. He was a healthy, nurtured boy.
But one night in January 2017, the mother was overwhelmed with tiredness while breast-feeding her son in her bed and fell asleep. He died that night.
"His death in such very sad circumstances highlights the vigilance that must be maintained to ensure that every sleep for a baby is a safe sleep," the coroner said.