Inequalities in birth weight and maternal education: a time-series study from 1996 to 2013 in Brazil

Sonia Silvestrin,Marcelo Zubaran Goldani,Clécio Homrich Da Silva,Vânia Naomi Hirakata

doi:10.1038/s41598-020-65445-8

Abstract

Maternal education represents one of the most important social determinants of inequality in birth weight (BW) in developing countries. The present study sought to investigate secular trends in health inequality considering the difference in mean BW between extremes of maternal educational attainment in Brazil. Using a time-series design, data from 6,452,551 live births which occurred in all Brazilian state capitals from 1996 to 2013 were obtained from the Information System on Live Births. Secular trends of the difference in mean birth weight between low (<8 years of schooling) and high (≥12 years of schooling) educational attainment were analyzed. The main finding was that differences in mean birth weight between the two extremes of maternal educational attainment decreased over time. There was a significant decrease in mean BW in neonates born to mothers with higher educational attainment, and a slight increase in those born to mothers with lower educational attainment. One of the key factors involved in decreasing inequality was an increase in the number of antenatal visits. In view of these results, we conclude, that despite a slight increase of mean birth weight among mothers with low education, the reduction of inequality in pregnancy outcomes over time in Brazil is attributable to a worsening scenario for mothers who are better off rather than to improvements for the most vulnerable group of mothers.

Highlights

Maternal education represents one of the most important social determinants of inequality in birth weight (BW) in developing countries
In Brazil, we have shown in a previous study, despite significant improvements in maternal education, the rate of LBW remained stable around 8.5% of all life births during the last 15 years[8]
The results of this study showed a significant decline in mean of birth weight among infants born to mothers with a higher education level, leading to a significant reduction of general mean of birth weight during the time series

Summary

Introduction

Maternal education represents one of the most important social determinants of inequality in birth weight (BW) in developing countries. One of the key factors involved in decreasing inequality was an increase in the number of antenatal visits In view of these results, we conclude, that despite a slight increase of mean birth weight among mothers with low education, the reduction of inequality in pregnancy outcomes over time in Brazil is attributable to a worsening scenario for mothers who are better off rather than to improvements for the most vulnerable group of mothers. In Brazil, this situation regarding LBW is considered an epidemiological paradox and, according to some researchers, it can be explained by several factors, among them, the underreporting in the registry of low birth weight in the poorest and most vulnerable regions and, at the same time, the intense use of health care technologies such as cesarean sections and assisted reproduction techniques in other wealthier regions with more favorable socioeconomic conditions in the country[9]

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Conclusion