No improvement in socioeconomic inequalities in birthweight and preterm birth over four decades: a population-based cohort study

Abstract

BackgroundBirthweight and gestational age are associated with socioeconomic deprivation, but the evidence in relation to temporal changes in these associations is sparse. We investigated changes in the associations between socioeconomic status (SES) and birthweight and gestational age in Newcastle upon Tyne, North of England, during 1961–2000.MethodsWe used population-based data from hospital neonatal records on all singleton births to mothers resident in Newcastle (births with complete covariate information n = 113,182). We used linear regression to analyse the associations between neighbourhood SES and birthweight over the entire 40-year period and by decade, and logistic regression for associations with low birthweight (LBW) and preterm birth, adjusting for potential confounders.ResultsThere was a significant interaction between SES and decade of birth for birthweight (p = 0.028) and preterm birth (p < 0.001). Socioeconomic gradients were similar in each decade for birthweight outcomes, but for preterm birth, socioeconomic disparities were more evident in the later decades [for 1961–70, odds ratio (OR) was 1.1, 95% CI 0.9, 1.3, for the most deprived versus the least deprived quartile, while for 1991–2000, the corresponding OR was 1.5, 95% CI 1.3, 1.7]. In each decade, there was a significant decrease in birthweight adjusted for gestational age for the most deprived compared to the least deprived SES group [1961–1970: –113.4 g (95% CI–133.0, –93.8); 1991–2000: –97.5 g (95% CI–113.0, –82.0)], while there was a significant increase in birthweight in each SES group over time.ConclusionsSocioeconomic inequalities did not narrow over the four decades for birthweight and widened for preterm birth. Mean birthweight adjusted for gestational age increased in all socioeconomic groups, suggesting an overall increase in fetal growth.

Maternal socioeconomic factors and adverse perinatal outcomes in two birth cohorts, 1997/98 and 2010, in São Luís, Brazil

“…The results of our study oppose several studies in Brazil, Europe, Asia and North America, which found a higher risk of adverse perinatal outcomes among families of low socioeconomic class, education, and whose parents had manual jobs 13,[15][16][17][18][19]32,34,[40][41][42][43] . The main strength of this study is the use of a random population-based sample (a 1/3 of the births of São Luís' residents), which allows for generalization of the results for the general population of live births.…”

“…In Newcastle, England, between 1961 and 2000, PTB and LBW were higher in neonates of mothers from lower economic classes. In this same study, PTB rate increased in the lower classes but declined in the upper classes within the same period, but the factors involved in these changes have not yet been identified 16 . Despite studying different perinatal outcomes, both studies show the negative impact of low socioeconomic status in perinatal health.…”

Neonatal mortality in infants with low birth weigh

“…This group represents more than half of neonatal deaths, especially those who are born with extremely low birth weight (3) , confirmed by numerous studies that addresses low birth weight as one of the main factors associated with increased likelihood of death in the neonatal period (2,(6)(7)(8)(9)(10) .…”

“…However, it is essential to consider the social determinants that affect the occurrence of prematurity and low birth weight, and therefore, affecting greater risks for neonatal death. Among these determinants, we highlight maternal age and adverse living conditions, and the low educational level of the mother, among others (1,6,22) . Research that assessed infant mortality in newborn of very low birth weight in a public hospital in the city of Rio de Janeiro showed that infant of mothers with less than four years of study had a 2.5 times increased risk of neonatal death in comparison to those whose mothers that had more than eight years of study (14) .…”

“…Socioeconomic inequalities have an important role in the occurrence of low birth weight and premature birth (6) . Maternal social status has close relationship with their education.…”