One-year survival of extremely preterm infants after active perinatal care in Sweden.
BACKGROUND
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.


METHODS
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.


METHODS
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.


CONCLUSIONS
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.
Department of Obstetrics and Gynecology, Lund University Hospital, S-221 85 Lund, Sweden. karel.marsal@med.lu.se.
Fellman
Vineta
V
Hellström-Westas
Lena
L
Norman
Mikael
M
Westgren
Magnus
M
Källén
Karin
K
Lagercrantz
Hugo
H
Marsál
Karel
K
Serenius
Fredrik
F
Wennergren
Margareta
M
D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000401:mortality*; D015931:Intensive Care, Neonatal; D008297:Male; D009017:Morbidity; D018743:Perinatal Care; D054238:Perinatal Mortality; D011247:Pregnancy; D047928:Premature Birth; D011446:Prospective Studies; D012306:Risk; D016019:Survival Analysis; D013548:Sweden / Q000453:epidemiology