Related Experiment Videos
Before viability: a geographically based outcome study of infants weighing 500 grams or less at birth
R S Sauve1, C Robertson, P Etches
1Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada.
Insights
Survival without major disabilities is rare for infants born at 20 weeks gestation or more and weighing 500 g or less. Most survivors experience significant disabilities, highlighting the need for realistic parental expectations regarding extremely premature infant outcomes.
Area of Science:
- Neonatalogy
- Perinatology
- Developmental Pediatrics
Background:
- Infants born at 20 weeks gestation or more and weighing 500 g or less represent the most extreme end of prematurity.
- Understanding long-term survival and disability rates is crucial for parental counseling and clinical decision-making.
Purpose of the Study:
- To determine the likelihood of long-term survival and the absence of disabilities in a population-based cohort of extremely premature infants.
- To provide data on outcomes for infants born at the threshold of viability.
Main Methods:
- A 12-year historical cohort follow-up study was conducted in Alberta, Canada (1983-1994).
- Data were collected from birth and death certificates, hospital records, and longitudinal multidisciplinary follow-up examinations.
- Infants were categorized based on gestational age (≥20 weeks) and birth weight (≤500 g).
Main Results:
- Of 1193 infants, 68% were stillborn and 32% were live births.
- Neonatal intensive care was provided to 29.6% of live births; 15.9% of these survived to discharge, but 5 died post-discharge.
- Among 13 long-term survivors (followed to 36 months adjusted age), 4 had no major disabilities, 4 had one, and 5 had multiple disabilities.
Conclusions:
- Survival without major disabilities is rare (approximately 11% of those receiving intensive care), with most survivors experiencing one or more significant impairments.
- Survivors face risks including rehospitalization, growth issues, feeding problems, and potential learning/behavioral difficulties.
- Local population-based data are essential for informing parents about the realistic outcomes for extremely premature infants.
Objective:
The primary objective of this study was to determine the likelihood of long-term survival and avoidance of disabilities in a geographically based population of infants born at 20 weeks gestation or more and weighing 500 g or less at birth.
Study Design:
This was a 12-year historical cohort follow-up study of all infants born in this gestational age and birth weight category in the Province of Alberta, Canada, between 1983 and 1994. Data were collected from certificates of live births or stillbirths, death certificates, hospital records, and longitudinal multidisciplinary follow-up examinations.
Results:
One thousand one hundred ninety-three infants were of 20 weeks gestation or more, weighed 500 g or less, and were born between 1983 and 1994. Eight hundred eleven (68.0%) were stillborn and 382 (32.0%) were born alive. Among the latter, neonatal intensive care was provided in 113 (29.6%) and withheld in 269 (70.4%). The infants receiving intensive care were of heavier birth weight, later gestational age, higher antenatal risk scores, were more likely to be born in a level III center, to have received antenatal steroids, and to have been delivered by cesarean section. Of the infants receiving intensive care, 95 (84. 1%) died and 18 (15.9%) were discharged alive, but 5 of these died after discharge because of respiratory complications. The infants discharged alive had later gestational age, were more likely to be small for gestational age, singletons, treated with antenatal steroids, and to have been delivered by cesarean section. Maternal indications were described in the majority of cesarean sections done for live-born infants. The 13 infants who were long-term survivors were followed at ages 12 and 36 months adjusted age. Four had no serious disabilities, 4 had one disability (cerebral palsy or mental retardation), and 5 had multiple disabilities (cerebral palsy plus mental retardation with blindness in 2 cases and deafness in 1 case).
Conclusion:
The majority of infants born at gestational age 20 weeks or more weighing <500 g were stillborn. Among live births, neonatal intensive care was withheld in 70% and initiated in 30%. Of the latter, 11% survived to 36 months of age, and of these, 4 infants (31%), most of whom are small for gestational age, female infants, avoided major disabilities but 9 (69%) had one or more major disabilities. Survivors are prone to rehospitalizations early in life, slow growth, feeding problems, and minor visual difficulties; rates of learning-related and behavioral problems at school age are not yet known. Implications. Parents and caregivers faced with the impending delivery of an infant in this gestational age/birth weight category should understand that survival without multiple major disabilities is possible but rare. They should be made aware of local population-based results and not just isolated reports.