Mortality trends in extremely premature neonates: insights from the CDC WONDER database from 1999 to 2023

Rebecca Hammond ¹, Martin Phan ¹, Olivia Foley ¹

⁰Department of Medical Education, School of Medicine, Creighton University, Omaha, NE, United States.

Frontiers in Pediatrics +

|

December 8, 2025

View abstract on PubMed

Summary

Mortality for extremely premature infants decreased overall from 1999-2023, but disparities persist among racial groups and between urban and rural areas. Outcomes for extremely premature neonates are not evenly distributed across all demographic groups in the U.S.

Area Of Science

Neonatal Health
Public Health
Epidemiology

Background

Premature birth, especially extreme prematurity (born <28 weeks gestation), is a leading cause of infant morbidity and mortality.
Advances in antenatal and neonatal care have improved survival rates for extremely premature infants.
Understanding mortality trends and disparities is crucial for targeted interventions.

Purpose Of The Study

To evaluate trends in mortality rates for extremely premature neonates (<1 year old) in the United States from 1999 to 2023.
To determine if these mortality trends are evenly distributed across various demographic groups, including sex, race, region, and urban/rural locality.
To assess the impact of the COVID-19 pandemic on extreme prematurity mortality trends.

Main Methods

Utilized the CDC WONDER database for national infant mortality data (1999-2023).
Employed Joinpoint regression analysis to assess Crude Mortality Rate (CMR) trends, including Annual Percent Change (APC) and Average Annual Percent Change (AAPC).
Stratified data analysis by infant sex, race/ethnicity, geographic region, and urban versus rural location.

Main Results

A total of 92,917 deaths were recorded for extremely premature neonates from 1999-2023, with an overall significant decrease in CMR (AAPC -1.14%).
Significant CMR declines were observed for both males and females, and for Black/African American and White neonates.
Mortality rates decreased in urban areas but showed no significant decrease in rural areas; the West region showed a non-significant decline.

Conclusions

Despite overall improvements, significant disparities in extreme prematurity mortality persist among different demographic groups in the U.S.
Outcomes for extremely premature infants are not equitably distributed across racial and geographic lines.
No substantial changes in mortality trends were directly attributable to the COVID-19 pandemic during the study period.

Keywords:

United States demographic trends disparity mortality neonate prematurity

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