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One-year survival of extremely preterm infants after active perinatal care in Sweden
1, Vineta Fellman, Lena Hellström-Westas
1Department of Obstetrics and Gynecology, Lund University Hospital, S-221 85 Lund, Sweden. karel.marsal@med.lu.se.
Insights
Swedish infants born extremely preterm between 2004-2007 showed a 70% 1-year survival rate. Survival varied significantly by gestational age, from 9.8% at 22 weeks to 85% at 26 weeks.
Area of Science:
- Neonatalogy
- Perinatal Medicine
- Public Health
Background:
- Up-to-date information on infant survival after extremely preterm birth is crucial for evaluating perinatal care.
- This data informs clinical guidelines and parental counseling for high-risk births.
Purpose of the Study:
- To determine the 1-year survival rate for all infants born before 27 gestational weeks in Sweden.
- To analyze survival rates across different gestational ages (22-26 weeks).
- To identify factors associated with improved survival in extremely preterm infants.
Main Methods:
- A population-based prospective observational study was conducted in Sweden from 2004-2007.
- Included live-born and stillborn infants born before 27 gestational weeks.
- Assessed infant survival to 365 days and survival without major neonatal morbidity.
Main Results:
- Overall perinatal mortality was 45%, with 70% of live-born infants surviving to 1 year.
- Survival rates ranged from 9.8% at 22 weeks to 85% at 26 weeks.
- Tocolytic treatment, antenatal corticosteroids, surfactant treatment, and level III hospital birth were associated with lower infant death risk.
Conclusions:
- In Sweden (2004-2007), 1-year survival for infants born alive at 22-26 weeks was 70%.
- Survival rates demonstrated a strong positive correlation with increasing gestational age.
- Forty-five percent of 1-year survivors had no major neonatal morbidity, highlighting the challenges of extreme prematurity.
Context:
Up-to-date information on infant survival after extremely preterm birth is needed for assessing perinatal care services, clinical guidelines, and parental counseling.
Objective:
To determine the 1-year survival in all infants born before 27 gestational weeks in Sweden during 2004-2007.
Design, Setting, And Patients:
Population-based prospective observational study of extremely preterm infants (707 live-born and 304 stillbirths) born to 887 mothers in 904 deliveries (102 multiple births) in all obstetric and neonatal units in Sweden from April 1, 2004, to March 31, 2007.
Main Outcome Measures:
Infant survival to 365 days and survival without major neonatal morbidity (intraventricular hemorrhage grade >2, retinopathy of prematurity stage >2, periventricular leukomalacia, necrotizing enterocolitis, severe bronchopulmonary dysplasia). Associations between perinatal interventions and survival.
Results:
The incidence of extreme prematurity was 3.3 per 1000 infants. Overall perinatal mortality was 45% (from 93% at 22 weeks to 24% at 26 weeks), with 30% stillbirths, including 6.5% intrapartum deaths. Of live-born infants, 91% were admitted to neonatal intensive care and 70% survived to 1 year of age (95% confidence interval [CI], 67%-73%). The Kaplan-Meier survival estimates for 22, 23, 24, 25, and 26 weeks were 9.8% (95% CI, 4%-23%), 53% (95% CI, 44%-63%), 67% (95% CI, 59%-75%), 82% (95% CI, 76%-87%), and 85% (95% CI, 81%-90%), respectively. Lower risk of infant death was associated with tocolytic treatment (adjusted for gestational age odds ratio [OR], 0.43; 95% CI, 0.36-0.52), antenatal corticosteroids (OR, 0.44; 95% CI, 0.24-0.81), surfactant treatment within 2 hours after birth (OR, 0.47; 95% CI, 0.32-0.71), and birth at a level III hospital (OR, 0.49; 95% CI, 0.32-0.75). Among 1-year survivors, 45% had no major neonatal morbidity.
Conclusion:
During 2004 to 2007, 1-year survival of infants born alive at 22 to 26 weeks of gestation in Sweden was 70% and ranged from 9.8% at 22 weeks to 85% at 26 weeks.
