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Emily Oster

1 minute read Emily Oster

Emily Oster

Trends in Health for Extremely Preterm Babies

From the journals

Emily Oster

1 minute read

One of the most striking achievements of the medical system over the past 60 years or so is in the survival of preterm infants. In the 1960s, mortality rates were high even for infants born as late as 36 weeks. Improvements in technology, especially our understanding of respiratory support, have completely changed this landscape; in more recent data, 99% of infants born at 36 weeks survive.

Along with these improvements for late preterm infants (that’s 34 to 36 weeks), we’ve also seen improvements in survival for infants born extremely preterm. This paper, published in the journal Pediatrics in January 2024, uses data from 888 hospitals in the U.S. to track trends in survival and complications for infants born at 24 to 28 weeks between 1997 and 2021.

The graph below summarized one top line of the result, focusing on mortality.

There are a few key takeaways from this graph. First, mortality is declining dramatically over time, especially for the youngest babies. In 1997, less than 60% of infants born at 24 weeks survived; by 2021, this was over 70%. Second, survival improves quickly as gestational age increases. Roughly 95% of infants born at 28 weeks in this sample in 2021 survived. 

The authors see similar trends in other complications that are common in these infants. 

Although this paper largely seems to produce good news, the authors do note that the big improvements from roughly 2005 to 2012 have made way for only smaller improvements in the past decade. They speculate that our current technologies may have reached their limit, and further large survival improvements may require more substantial technological change.

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