Related Experiment Video
Updated: May 31, 2026
Modeling Ascending Vaginal Infection, Preterm Birth, and Neonatal Morbidity in Mice
Published on: October 10, 2025
Extremely preterm infant mortality rates and cesarean deliveries in the United States
Beau Batton1, Christopher Burnett, Steven Verhulst
1From the Departments of Pediatrics and Statistics and Research Consulting, Southern Illinois University School of Medicine, Springfield, Illinois.
Insights
Cesarean delivery rates for extremely preterm infants increased significantly from 1999 to 2005. This rise in cesarean births did not improve infant mortality rates for these vulnerable newborns.
Area of Science:
- Perinatal medicine
- Neonatology
- Public health
Background:
- Extremely preterm infants (born <28 weeks gestation) represent a vulnerable population with high mortality.
- Trends in delivery modes and outcomes for this group are crucial for clinical practice and public health.
- Understanding cesarean delivery trends is important for optimizing care for extremely preterm neonates.
Purpose of the Study:
- To estimate trends in infant mortality rates for extremely preterm infants.
- To assess changes in cesarean delivery rates among extremely preterm infants in the U.S.
- To determine the association between cesarean delivery trends and infant mortality in this population.
Main Methods:
- National population-based study utilizing public data from the CDC.
- Analysis of extremely preterm infants (22 0/7 to 27 6/7 weeks gestation) born between 1999 and 2005.
- Examination of infant mortality rates and cesarean delivery rates over the study period.
Main Results:
- Annual extremely preterm births increased by 7% from 1999 to 2005.
- Infant mortality rate for extremely preterm infants remained stable (33-34%), despite a rise in cesarean deliveries from 43% to 54%.
- Cesarean delivery rates increased across all gestational ages, while mortality rates remained largely unchanged, except for a slight decrease at 24 weeks gestation.
Conclusions:
- A significant increase in cesarean delivery rates for extremely preterm infants occurred between 1999 and 2005.
- The rise in cesarean deliveries was not linked to a reduction in infant mortality for infants born before 28 weeks gestation.
- Findings suggest current trends in cesarean delivery for extremely preterm infants may not be improving survival rates.
Objectives:
To estimate trends in infant mortality rates and cesarean delivery rates for extremely preterm infants born in the United States.
Methods:
This national population-based study used public data from the Centers for Disease Control and Prevention to investigate extremely preterm infants born alive between 22 0/7 and 27 6/7 weeks of gestational age from 1999 to 2005.
Results:
There were 177,552 extremely preterm infant births (fewer than 1% of all births) from 1999 to 2005. The number of annual extremely preterm births increased by 7% compared with a 4.5% increase for births at all gestations. During the study years, the extremely preterm infant mortality rate (percentage of infants who died in the first year) remained steady (range 33-34%; P=.22), whereas the cesarean delivery rate increased from 43% to 54% (P<.001). The infant mortality rate after cesarean delivery increased from 24% to 26% (P=.012). At each gestational age, the annual cesarean delivery rate increased over time (P<.001 for each), whereas gestational age-specific infant mortality rates were unchanged except for a 2% decline from 2004 to 2005 for infants born at 24 weeks of gestation (P=.01).
Conclusion:
A significant rise in the cesarean delivery rate in the United States from 1999 to 2005 for infants born at less than 28 weeks of gestation was not associated with an improvement in the infant mortality rate.
Related Concept Videos
01:28Development of the Oral Microbiota
01:07Teratogenicity