Map to target NZ's rising preterm birth rates

When PhD researcher Cristal Salatas talked to her mum about her plan to study the distribution of preterm births in New Zealand as a way to help reverse a worrying increase in prematurity, she learnt something she wasn’t expecting: her brother had been born frighteningly early. 

Preterm birth is defined as a baby being born at less than 37 weeks gestation; Salatas’ brother was only 27 weeks. Preterm babies’  organs aren’t properly developed – they may have heart problems or trouble breathing. Longer term complications can include cerebral palsy, hearing and sight problems, developmental delays, and behavioural and mental health issues. Prem babies are also at a higher risk of asthma and sudden infant death syndrome.  

Salatas knew only too well her brother’s physical and cognitive struggles, and it only served to strengthen her resolve to try to do something that could make a difference.

Her answer is a map; an interactive, data-rich visualisation which brings together a wide variety of bits of information around preterm birth, to help work out what is important – and maybe what isn’t. 

The map will include, for example: census data; preterm birth figures from different health facilities; statistics on deprivation; sociodemographic factors like ethnicity, education level and income; environmental factors like water quality; and the prevalence of different food options in the neighbourhood where the mum lives (from junk food to dairies to fresh food markets). Then it will add potential stress factors like natural disasters, Covid infections, and even violent events.

“I want to see what could potentially be an influencer; what we can potentially do to prevent the problem getting worse,” Salatas says.

Every year, millions of babies worldwide are born preterm, and prematurity is the leading cause of death in children under five. A study from the World Health Organization and others found an estimated 13.4 million babies were born early in 2020 – just under 10 percent of all births. 

And while the global figure has fallen five percent over the last 30 years, in New Zealand and some other developed countries – such as the US, where Salatas grew up – it’s on the rise.

The number of Kiwi babies born prematurely is about 8 percent of total births, and this has been increasing since 2015.

Salatas did her Masters’ research in Africa, focusing on maternal and newborn mortality, but then worked for the Colorado State Health Department as lead epidemiologist and data scientist responsible for mapping and tracking Covid cases and trends in wastewater.

So when she was thinking about PhD research into preterm births, she realised using the Geographic Information System (GIS) mapping software she already knew made sense.

“That software – you can do what you want with it. The coordinates are pre-made for each location, so whenever a hospital has preterm birth data – right now we have 2003-2021 data – I put it in for that hospital.

“Then there’s another layer for all the food outlets – where are all the fast-food locations around those hospitals, the junk food, but also the healthy options and the convenience stores. And then I add where were the earthquakes in that timeframe, the volcanic eruptions, Covid cases, and any civil unrest that might have happened, like the mosque shooting.

“I want to see how everything can have an impact, so we can see how we can potentially reduce those preventable ones.”The next step is to try to form patterns or trends around the data, Salatas says.

“So then we can tell the experts, the healthcare providers and the district health boards, so we can prevent the statistics getting worse.

”For example, Liggins Institute research found what a mum eats before and during pregnancy can have an impact on whether her baby is born early. 

Meanwhile, 2020 data shows  the rate of preterm birth differs by ethnic groupings. The overall figure is 7.9 percent, but for Māori it’s 9 percent; it’s 8.8 percent for Indian people, 8.1 percent for Pacific, and 7.1 percent for Pākehā.

There are also differences by region across the former district health board areas, with the prevalence ranging from 5.6 percent to 13.1 percent.

Professor Frank Bloomfield, Deputy Vice Chancellor (Research) at the University of Auckland and an expert in the health and nutrition of premature babies, says the map will provide data “to collaborate with policymakers and healthcare professionals to translate research findings into real-world strategies for reducing preventable preterm births in New Zealand.

“Further, the map provides valuable insights for future research, policy development, and interventions to promote healthy pregnancies and prevent preterm births in New Zealand.”

Listen to Cristal Saletas on 95bFM’s Ready Steady Learn

Learn more about postgraduate study at the Liggins Institute