Survival and Major Morbidity of Extremely Preterm Infants: A Population-Based Study.
To assess the rates of mortality and major morbidity among extremely preterm infants born in California and to examine the rates of neonatal interventions and timing of death at each gestational age.



A retrospective cohort study of all California live births from 2007 through 2011 linked to vital statistics and hospital discharge records, whose best-estimated gestational age at birth was 22 through 28 weeks. Major morbidities were based on International Classification of Diseases, Ninth Revision, Clinical Modification codes. Survival beyond the first calendar day of life and procedure codes were used to assess attempted resuscitation after birth.



A total of 6009 infants born at 22 through 28 weeks' gestation were included. Survival to 1 year for all live births ranged from 6% at 22 weeks to 94% at 28 weeks. Seventy-three percent of deaths occurred within the first week of life. Major morbidity was present in 80% of all infants, and multiple major morbidities were present in 66% of 22- and 23-week infants. Rates of resuscitation at 22, 23, and 24 weeks were 21%, 64%, and 93%, respectively. Survival after resuscitation was 31%, 42%, and 64% among 22-, 23-, and 24-week infants, respectively. Improved survival was associated with increased birth weight, female sex, and cesarean delivery (P < .01) for resuscitated 22-, 23-, and 24-week infants.



In a population-based study of extreme prematurity, infants ≤24 weeks' gestation are at highest risk of death or major morbidity. These data can help inform recommendations and decision-making for extremely preterm births.
Departments of Pediatrics, james.anderson3@ucsf.edu.
James G
JG
Anderson
Department of Pediatrics, University of California San Diego, La Jolla, California.
Rebecca J
RJ
Baer
Departments of Pediatrics.
J Colin
JC
Partridge
Obstetrics, Gynecology, and Reproductive Sciences, and.
Miriam
M
Kuppermann
School of Nursing, University of California San Francisco, San Francisco, California; and.
Linda S
LS
Franck
Obstetrics, Gynecology, and Reproductive Sciences, and.
Larry
L
Rand
Epidemiology and Biostatistics, and.
Laura L
LL
Jelliffe-Pawlowski
Departments of Pediatrics.
Elizabeth E
EE
Rogers
D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D012189:Retrospective Studies; D015996:Survival Rate