Review and special articleSocioeconomic Disparities in Adverse Birth Outcomes: A Systematic Review
Introduction
Adverse birth or pregnancy outcomes—defined here as preterm birth, low birth weight, and small for gestational age—have serious health consequences not only during infancy1, 2 but also throughout childhood3, 4 and in adulthood.5, 6, 7, 8 Socioeconomic and racial/ethnic disparities in preterm birth and low birth weight have been relatively intractable over the past decade.9 Although routine public health statistics in the U.S. historically have been reported by race or ethnic group,10 socioeconomic information on disparities in birth outcomes generally has been limited to maternal educational level. The most recent systematic review of this topic was published in 1987,11 whereas a critical review published in 2000 focused on etiologic factors mediating socioeconomic disparities in pregnancy outcomes.12 Building on those earlier studies, this systematic review focused on the English-language literature from industrialized nations since 2000 that examined links between socioeconomic factors and birth outcomes, with specific attention to the strength and consistency of effects across socioeconomic measures, birth outcomes, and populations.
Section snippets
Evidence Acquisition
Methods for the review were based on those outlined in the Cochrane Collaboration's Handbook for Systematic Reviews of Health Promotion and Public Health Interventions13 and in the Meta-Analysis of Observational Studies in Epidemiology guidelines14 for the reporting of systematic reviews and meta-analyses of observational studies. The systematic review team included five core members: two master's-level researchers with advanced training in epidemiology and biostatistics and three
Evidence Synthesis
Ninety-three of the 106 studies reported a significant association between a socioeconomic measure and an adverse birth outcome, either in the overall study population or in a population subgroup. All 93 of these studies found that adverse birth outcomes were most prevalent among women in the most socioeconomically disadvantaged groups, although two studies also found evidence that higher levels of neighborhood poverty or unemployment were associated with lower prevalence of low birth weight
Discussion
Ninety-three of the 106 studies included in the present review reported a significant association between at least one socioeconomic measure and one birth outcome, either in the overall study population or in a racial/ethnic subgroup. Wherever a significant association was observed, socioeconomic disadvantage was associated with increased risk of adverse birth outcomes across socioeconomic measures, birth outcomes, and countries represented in the current review, except for the two studies that
References (73)
Racial and ethnic variation in low birthweight in the U.S.: individual and contextual determinants
Health Place
(1999)- et al.
Sociocultural factors that affect pregnancy outcomes in two dissimilar immigrant groups in the U.S.
J Pediatr
(2006) - et al.
Neighborhood economic disadvantage, violent crime, group density, and pregnancy outcomes in a diverse, urban population
Soc Sci Med
(2007) Racial and ethnic variation in low birthweight in the U.S.: individual and contextual determinants
Health Place
(1999)- et al.
Modeling community-level effects on preterm birth
Ann Epidemiol
(2003) - et al.
Neighborhood socioeconomic status, maternal race and preterm delivery: a case–control study
Ann Epidemiol
(2002) - et al.
Race and ethnic differences in determinants of preterm birth in the USA: broadening the social context
Soc Sci Med
(2005) - et al.
Neighborhood crime, deprivation, and preterm birth
Ann Epidemiol
(2006) The relevance of multilevel statistical methods for identifying causal neighborhood effects
Soc Sci Med
(2004)The influence of maternal childhood and adulthood social class on the health of the infant
Soc Sci Med
(2006)