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Day-by-day postnatal survival in very low birth weight infants
Mohamed A Mohamed1, Ayman Nada, Hany Aly
1The George Washington University Medical Center, Newborn Services, Washington, DC 20037, USA. mmohamed@mfa.gwu.edu
Insights
Very low birth weight (VLBW) infants surviving the first few days show significantly improved survival chances. This study provides day-by-day postnatal survival rates for VLBW infants by birth weight category.
Area of Science:
- Neonatalogy
- Pediatric Survival Analysis
- Public Health Data Analysis
Background:
- Established postnatal survival rates for very low birth weight (VLBW) infants lack granularity for those surviving initial days.
- Existing data does not distinguish between infants who die shortly after birth and those who survive the critical early postnatal period.
Purpose of the Study:
- To develop standardized, day-by-day postnatal survival curves for VLBW infants.
- To provide more precise survival predictions based on early postnatal viability.
Main Methods:
- Analysis of the National Inpatient Sample Database (1997-2004) for infants <1500g birth weight.
- Classification of infants into four birth weight groups: <500g, 500-749g, 750-999g, and 1000-1499g.
- Calculation of postnatal survival rates at specific intervals (birth, day 1, 2, 3, 4-5, 6-7, 14, 21, 28, >28 days).
Main Results:
- Overall survival for infants <500g was 8%; survival increased to 50% if they survived the first 3 days.
- Infants 500-749g had 50% overall survival, rising to 70% after 3 days and 80% by week one.
- No significant improvement in overall survival rates was observed across birth weight categories during the study period.
Conclusions:
- VLBW infants who overcome the initial critical postnatal days have substantially higher survival probabilities.
- Day-by-day survival prediction curves can be established for VLBW infants across different birth weight strata until discharge.
Objectives:
Postnatal survival rates of very low birth weight (VLBW) infants are well established for each birth weight or gestational age category. These figures do not differentiate viable infants who survive the first few days of life from extremely immature ones who die shortly after birth. This study aimed to develop standardized curves for day-by-day postnatal survival rates of VLBW infants.
Methods:
National Inpatient Sample Database and its pediatrics-only subportion were analyzed for the years 1997-2004. Infants with birth weight <1500 g were included in the study. Infants were classified according to their birth weight into 4 groups: <500, 500 to 749, 750 to 999, and 1000 to 1499 g. Postnatal survival rates were calculated for each group at birth and at 1, 2, 3, 4 to 5, 6 to 7, 14, 21, 28, and >28 postnatal days.
Results:
Overall survival for infants with birth weight <500 g was 8%. Those who lived through the first 3 days of life had a chance of survival up to 50%. Infants in the 500- to 749-g group had overall survival rate of 50% that increased to 70% if they survived through the third day and 80% by the end of the first week. There was no improvement in the overall survival of any birth weight category over the years of the study.
Conclusions:
VLBW infants who survive the first few postnatal days have a considerably better chance for life. We can predict postnatal survival chances for each birth weight category on a day-by-day basis until discharge.
