Factors associated with low birth weight at term: a population-based linkage study of the 100 million Brazilian cohort

Ila R Falcão,Natanael J Silva,Naiá Ortelan,Rita De Cássia Ribeiro-Silva,Laura C Rodrigues,Rosemeire L Fiaccone,Aline Dos S Rocha,Maria Yury Ichihara,Marcia F De Almeida,Mauricio L Barreto,Enny S Paixao

doi:10.1186/s12884-020-03226-x

Abstract

BackgroundFactors associated with low birth weight at term (TLBW), a proxy for intrauterine growth restriction (IUGR), are not well-elucidated in socioeconomically vulnerable populations. This study aimed to identify the factors associated with TLBW in impoverished Brazilian women.MethodsRecords in the 100 Million Brazilian Cohort database were linked to those in the National System of Information on Live Births (SINASC) to obtain obstetric, maternal, birth and socioeconomic data between 2001 and 2015. Multivariate logistic regression was performed to investigate associations between variables of exposure and TLBW.ResultsOf 8,768,930 term live births analyzed, 3.7% presented TLBW. The highest odds of TLBW were associated with female newborns (OR: 1.49; 95% CI: 1.47–1.50), whose mothers were black (OR: 1.20; 95% CI: 1.18–1.22), had a low educational level (OR: 1.57; 95% CI: 1.53–1.62), were aged ≥35 years (OR: 1.44; 95% CI: 1.43–1.46), had a low number of prenatal care visits (OR: 2.48; 95% CI: 2.42–2.54) and were primiparous (OR: 1.62; 95% CI: 1.60–1.64). Lower odds of TLBW were found among infants whose mothers lived in the North, Northeast and Center-West regions of Brazil compared to those in the South.ConclusionMultiple aspects were associated with TLBW, highlighting the need to comprehensively examine the mechanisms underlying these factors, especially in more vulnerable Brazilian populations, in order to contribute to the elaboration of health policies and promote better conditions of life for poor and extremely poor mothers and children.

Highlights

Factors associated with low birth weight at term (TLBW), a proxy for intrauterine growth restriction (IUGR), are not well-elucidated in socioeconomically vulnerable populations
To further investigate factors associated with Low birth weight at term (TLBW), this study considered data between 2001 and 2015 from the 100 Million Brazilian Cohort linked to the National Live Birth System (SINASC)
The odds of TLBW were higher among infants born to women who: self-declared skin color as black (OR: 1.20; 95% CI: 1.18–1.22), were unmarried (OR: 1.08; 95% CI: 1.07–1.09), had a low level of schooling (OR: 1.57; 95% CI: 1.53–1.62), had no prenatal visits (OR: 2.48; 95% CI: 2.42–2.54), were aged between 35 and 49 years (OR: 1.44; 95% CI: 1.43–1.46), gave birth for the first time (OR: 1.62; 95% CI: 1.60– 1.64) and were female (OR: 1.49; 95% CI: 1.47–1.50)

Summary

Introduction

Factors associated with low birth weight at term (TLBW), a proxy for intrauterine growth restriction (IUGR), are not well-elucidated in socioeconomically vulnerable populations. Studies in low- and middle-income countries indicate that socioeconomic factors, including education, income, an urban/rural living environment, region of residence and domiciliary conditions, as well as access to prenatal care, are important determinants of pregnancy and birth weight outcomes [4, 10,11,12,13,14, 16,17,18,19,20,21,22,23]. Several studies have examined the determinants of TLBW, factors associated with TLBW remain unelucidated among socioeconomically vulnerable populations living in low- and middle- income countries, such as Brazil. The linkage of these two datasets enabled us to investigate the factors associated with TLBW in the Brazilian population living in poverty and extreme poverty, with the hope of contributing to the development of intervention strategies aimed at minimizing LBW

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