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Updated: May 23, 2026
Transcutaneous Microcirculatory Imaging in Preterm Neonates
Published on: December 31, 2015
Improving survival of extremely preterm infants born between 22 and 25 weeks of gestation
Kathy L Kyser1, Frank H Morriss, Edward F Bell
1Department of Obstetrics and Gynecology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA. kathy-kyser@uiowa.edu
Insights
Survival rates for extremely premature infants born between 2000-2009 exceeded predictions, with antenatal corticosteroids significantly improving outcomes. Improved survival odds were observed throughout the decade for these high-risk neonates.
Area of Science:
- Neonatalogy
- Perinatology
- Public Health
Background:
- Extremely premature infants (22-25 weeks gestation) have historically low survival rates.
- Predictive models for survival often rely on factors like gestational age, birth weight, and sex.
Purpose of the Study:
- To compare observed versus predicted survival rates for extremely premature infants born between 2000-2009.
- To identify current predictors of survival in this population.
- To assess trends in survival rates over the decade.
Main Methods:
- Retrospective cohort analysis of 237 inborn neonates (22-25 weeks gestation) without major congenital anomalies.
- Comparison of observed survival rates with predicted rates using a validated web-based calculator.
- Multivariable logistic regression to identify significant predictors, including birth year.
Main Results:
- Observed survival rates consistently exceeded predicted rates across all gestational ages (22-25 weeks).
- Antenatal corticosteroid administration (96% of cases) was a significant predictor of survival (OR 5.27).
- Other significant predictors included female sex, gestational age, 1-minute Apgar score, and birth year, with increasing odds of survival over time.
Conclusions:
- Survival rates for extremely premature infants born in the 2000s surpassed predicted rates.
- Aggressive management, including antenatal corticosteroid administration, significantly improved survival.
- There was a demonstrable increase in survival odds during the study decade.
Objective:
To estimate observed compared with predicted survival rates of extremely premature infants born during 2000-2009, to identify contemporary predictors of survival, and to determine if improved survival rates occurred during the decade.
Methods:
We conducted a retrospective cohort analysis of 237 inborn neonates without major congenital anomalies born from 2000 to 2009 after 22 to 25 completed weeks of gestation. Observed survival rates at each gestational age were compared with predicted survival rates based on gestational age, birth weight, sex, singleton or multiple gestation, and antenatal corticosteroid administration estimated by a Web-based calculator that was derived from 1998 to 2003 outcomes of a large national cohort. Multivariable logistic regression analysis was used to identify significant predictors of survival of the study cohort, including year of birth.
Results:
Survival rates for the decade by gestational age (compared with predicted rates) were: 22 weeks, 33% (compared with 19%); 23 weeks, 58% (compared with 38%); 24 weeks, 87% (compared with 58%); and 25 weeks, 85% (compared with 70%). Antenatal corticosteroids were administered in 96% of pregnancies. Variables that significantly predicted survival and their odds ratios (OR) with 95% confidence intervals (CI) are: antenatal corticosteroid administration (OR 5.27, CI 1.26-22.08); female sex (OR 3.21, CI 1.42-7.26); gestational age (OR 1.89, CI 1.27-2.81); 1-minute Apgar score (OR 1.39, CI 1.15-1.69); and birth year (OR 1.17, CI 1.02-1.34). The number needed to treat with any antenatal corticosteroid therapy to prevent one death was 2.4.
Conclusion:
In this single-institution cohort treated aggressively (antenatal corticosteroid administration [even if less than 24 weeks], tocolysis until steroid course complete, cesarean for fetal distress) by perinatologists and neonatologists, survival rates at 22-25 weeks of gestation age for inborn infants during the 2000s exceeded predicted rates, with increasing odds of survival during the decade. Antenatal corticosteroid administration had a significant effect on survival.
Level Of Evidence:
II.
