Mortality risk in preterm and small-for-gestational-age infants in low-income and middle-income countries: a pooled country analysis

Abstract

Summary Background Babies with low birthweight (<2500 g) are at increased risk of early mortality. However, low birthweight includes babies born preterm and with fetal growth restriction, and not all these infants have a birthweight less than 2500 g. We estimated the neonatal and infant mortality associated with these two characteristics in low-income and middle-income countries. Methods For this pooled analysis, we searched all available studies and identified 20 cohorts (providing data for 2 015 019 livebirths) from Asia, Africa, and Latin America that recorded data for birthweight, gestational age, and vital statistics through 28 days of life. Study dates ranged from 1982 through to 2010. We calculated relative risks (RR) and risk differences (RD) for mortality associated with preterm birth (<32 weeks, 32 weeks to <34 weeks, 34 weeks to <37 weeks), small-for-gestational-age (SGA; babies with birthweight in the lowest third percentile and between the third and tenth percentile of a US reference population), and preterm and SGA combinations. Findings Pooled overall RRs for preterm were 6·82 (95% CI 3·56–13·07) for neonatal mortality and 2·50 (1·48–4·22) for post-neonatal mortality. Pooled RRs for babies who were SGA (with birthweight in the lowest tenth percentile of the reference population) were 1·83 (95% CI 1·34–2·50) for neonatal mortality and 1·90 (1·32–2·73) for post-neonatal mortality. The neonatal mortality risk of babies who were both preterm and SGA was higher than that of babies with either characteristic alone (15·42; 9·11–26·12). Interpretation Many babies in low-income and middle-income countries are SGA. Preterm birth affects a smaller number of neonates than does SGA, but is associated with a higher mortality risk. The mortality risks associated with both characteristics extend beyond the neonatal period. Differentiation of the burden and risk of babies born preterm and SGA rather than with low birthweight could guide prevention and management strategies to speed progress towards Millennium Development Goal 4—the reduction of child mortality. Funding Bill & Melinda Gates Foundation.

Benefits and Risks of Antiretroviral Therapy for Perinatal HIV Prevention

“…5,6 In resource-limited settings, preterm delivery and low birth weight can be associated with increased morbidity and increased newborn or later postnatal mortality. [8][9][10][11] Reassuringly, the rate of very preterm delivery did not differ significantly between the zidovudine-alone group and the group assigned to zidovudine-based ART (periods 1 and 2) or the group assigned to tenofovir-based ART (period 2). However, the rate of very preterm delivery differed significantly between the two ART groups during period 2 (2.6% with zidovudine-based ART vs. 6.0% with tenofovir-based ART, P = 0.04), as did early infant mortality (correlated with very pre-term delivery) (0.6% vs. 4.4%, P<0.001).…”

Analysis of fetal growth restriction in pregnancy in subjects attending in an obstetric clinic of a tertiary care teaching hospital

“…5 Katz et al in a pooled analysis of 20 cohorts (total population 2015019 live births) from Asia, Africa, and Latin America studied the mortality risk in preterm and small for gestational age infants in low income and middle income countries. 27 Kramer et al, in their systematic review of 16 RCTs and quasi experimental studies on balanced energy protein supplementation to pregnant women reported reduction in incidence of SGA (RR 0.66, 95% CI 0.49-0.89), stillbirths (RR 0.62, 95% CI 0.40-0.98) and improved birth weight (Mean difference of 73g, 95% CI 30-117). 28 Cochrane systematic review of 21 RCTs on multiple micronutrient supplementation to pregnant women in comparison with two or fewer micronutrients resulted in a significant effect on low birth weight (RR 0.88, 95% CI 0.85-0.91), SGA (RR 0.89, 95% CI 0.83-0.96) and preterm birth (RR 0.97, 95% CI 0.94-0.99).…”

Prevalencias de bajo peso y pequeño para la edad gestacional en Argentina: comparación entre el estándar INTERGROWTH-21st y una referencia argentina

“…En contraste con la población altamente seleccionada de INTERGROWTH-21 st , es esperable que la población argentina tenga mayores exposiciones a factores asociados al estilo de vida, patologías obstétricas y cesáreas electivas que contribuyen a los nacimientos prematuros y restricción del crecimiento fetal. Debido a que los RN prétermino y PEG tienen el mayor riesgo de mortalidad neonatal e infantil, 14 es crítico identificarlos para la prevención secundaria y terciaria de discapacidad y mortalidad.…”

“…Este riesgo aumenta en los neonatos PEG pretérminos. 14,26 La incorporación a nivel epidemiológico de BP y PEG, junto con otros indicadores, como el BPN, para evaluar el riesgo de muerte infantil y resultados adversos en salud permitiría alcanzar mejores resultados en las políticas destinadas a mejorar la salud infantil.…”