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Variation in early neonatal mortality for different types of fetal growth retardation
J D Haas1, H Balcazar, L Caulfield
1Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853.
Insights
Premature birth and fetal growth restriction significantly increase early infant mortality risk. Disproportionately growth-retarded infants face the highest mortality, highlighting the need for targeted interventions.
Area of Science:
- Neonatal Health
- Perinatal Epidemiology
- Pediatric Mortality
Background:
- Early postnatal mortality remains a critical global health concern.
- Fetal growth restriction and prematurity are major contributors to infant deaths.
- Understanding the specific risks associated with different types of growth abnormalities is crucial for intervention.
Purpose of the Study:
- To characterize early postnatal mortality rates in relation to fetal growth retardation and prematurity.
- To compare mortality risks among infants with proportionate and disproportionate growth retardation.
- To analyze these patterns in two distinct urban populations.
Main Methods:
- Analysis of birth and first 48-hour death records for over 22,000 liveborn infants.
- Categorization of infants based on gestational age (preterm vs. term) and birth weight (light-for-gestational-age).
- Classification of light-for-gestational-age infants by proportionate (normal Rohrer's index) and disproportionate (low Rohrer's index) growth retardation.
Main Results:
- Infants born before 37 weeks of gestation had a 23-100 fold increased mortality risk compared to term infants.
- Proportionately growth-retarded infants had nearly double the mortality risk of appropriate-weight infants.
- Disproportionately growth-retarded infants exhibited a 2.9-5.7 times higher mortality rate than appropriate-weight infants.
Conclusions:
- Prematurity and fetal growth restriction are significant risk factors for early infant mortality.
- Disproportionate fetal growth retardation poses a substantially higher mortality risk than proportionate growth retardation.
- Consistent mortality patterns across different populations underscore the universal impact of these conditions.
Abstract:
Birth and first-48-hr death records were analyzed for 10,024 liveborn infants in Mexico City and 12,786 liveborn infants in Santa Cruz, Bolivia. The objective of the analysis was to characterize the early postnatal mortality rates for different types of fetal growth retardation and prematurity. Infants who were delivered prior to 37 weeks of gestation had 23-100 times the mortality risk of infants born at full term and normal weight. Light-for-gestational-age infants (birth weight less than 2,900 g) were further divided into proportionately growth-retarded with normal Rohrer's index (weight/height) and disproportionately growth-retarded with low Rohrer's index. The proportionately growth-retarded infant had nearly twice the mortality of the full-term, appropriate-weight infants, whereas the disproportionately growth-retarded infants had 2.9-5.7 times the mortality rate of the full-term, appropriate-weight infants. There were some differences between samples in mortality rates and prevalence of the different classes of small infants, but the pattern of mortality within samples was consistent between samples.