Preterm babies do better in a larger NICU

"The first hours of these babies' lives can be crucial, which means it is essential to give them expert care at this time," says Sam Watson. (Credit: Official U.S. Navy Page/Flickr)

The first hours of life for a preterm baby are critical, and expert care can mean the difference between life and death.

New research shows babies are less likely to die if they are admitted to high-volume neonatal units rather than smaller NICUs.

Researchers analyzed data from 165 neonatal units across the United Kingdom. They found babies born at less than 33 weeks gestation were 32 percent less likely to die if they were admitted to high-volume units, compared to low volume. For babies born at less than 27 weeks the effect was greater, with the odds of dying almost reduced by half when they were admitted to high-volume units, compared to low volume.

“One possible explanation for our results could be that those neonatal units delivering a greater volume of care provide the clinicians who work there with more experience,” says Sam Watson from the University of Warwick’s Medical School and Department of Economics. “The first hours of these babies’ lives can be crucial, which means it is essential to give them expert care at this time.”

“It is also possible that economies of scale play a role, in that the larger and busier units have more resources to invest in technology and facilities. However more research is needed to tease out the possible explanations and inform policy effectively.”

High vs low volume

The team analyzed data for 20,554 babies born at less than 33 weeks and for 2,559 babies born at less than 27 weeks. Twenty-four percent of the neonatal units were classified as high volume and 46.4 percent of infants born at less than 33 weeks were born in hospitals with a high-volume neonatal unit.


For this study high-volume neonatal units were defined as those that provide more than 3,480 care days to preterm babies per year. Several possible factors that could influence the statistical analysis were taken into account including age, birth weight, and sex of the baby.

“Our research shows that neonatal units that are larger and busier in terms of the amount of care they provide to preterm babies are more likely to show better clinical outcomes for these vulnerable infants,” says Professor Neena Modi from the Department of Medicine, Imperial College London. “This supports the networked approach that centralizes the delivery of specialized neonatal care in high volume units and enables women at risk to be transferred to these units to receive the care they need.”

Transfer risks

There has been much debate about the organization of critical care services for newborn babies, especially in relation to the volume and intensity of care units. In 2003 the UK created a model of networked, regionalized units to facilitate the transfer of preterm babies to higher care specialist units (NICUs), while also maintaining access to less specialized, low-volume units for those mothers and babies less at risk. These are now known as English Operational Delivery Networks. The results of this study support this approach but the researchers call for a need to further evaluate the effect of the transfers and to consider ways to improve procedures surrounding them.

“Our study indicates that ensuring very preterm babies, particularly those born at less than 27 weeks, are delivered in hospitals with high-volume neonatal units improves their outcome, but there could be a knock-on effect on other patient groups if smaller neonatal units are closed,” Watson explains. “Babies who are not born so early but who are still vulnerable may have to travel far from home as a consequence and this is why further research is urgently needed.”

Researchers from the University of Leicester and University College London also collaborated on the study, which appears in BMJ Open.

Funding for the research came from Bliss and the economics department at the University of Warwick.

Source: University of Warwick