U-Shaped Association between Maternal Hemoglobin and Low Birth Weight in Rural Bangladesh.

Rebecca M Carpenter,Rashidul Haque,Vanessa Thorsten,Elizabeth M Mcclure,Genevieve R Lyons,Md Shahjahan Siraj,William A Petri,Qazi S Rahman,Sk Masum Billah

doi:10.4269/ajtmh.21-0268

Abstract

ABSTRACT.Low birth weight (LBW) is associated with a higher risk of neonatal mortality and the development of adult-onset chronic disease. Understanding the ongoing contribution of maternal hemoglobin (Hgb) levels to the incidence of LBW in South Asia is crucial to achieve the World Health Assembly global nutrition target of a 30% reduction in LBW by 2025. We enrolled pregnant women from the rural Tangail District of Bangladesh in a Maternal Newborn Health Registry established under The Global Network for Women’s and Children’s Health Research. We measured the Hgb of pregnant women at enrollment and birth weights of all infants born after 20 weeks gestation. Using logistic regression to adjust for multiple potential confounders, we estimated the association between maternal Hgb and the risk of LBW. We obtained Hgb measurements and birth weights from 1,665 mother–child dyads between July 2019 and April 2020. Using trimester-specific cutoffs for anemia, 48.3% of the women were anemic and the mean (±SD) Hgb level was 10.6 (±1.24) g/dL. We identified a U-shaped relationship where the highest risk of LBW was seen at very low (< 7.0 g/dL, OR = 2.00, 95% CI = 0.43–7.01, P = 0.31) and high (> 13.0 g/dL, OR = 2.17, 95% CI = 1.01–4.38, P = 0.036) Hgb levels. The mechanisms underlying this U-shaped association may include decreased plasma expansion during pregnancy and/or iron dysregulation resulting in placental disease. Further research is needed to explain the observed U-shaped relationship, to guide iron supplementation in pregnancy and to minimize the risk of LBW outcomes.

Highlights

Low birth weight (LBW) continues to be a pressing global health concern as approximately 20 million babies are born each year with a weight of, 2,500 grams.[1]
In 2012, the WHO set global nutrition targets under the Millennium Development Goals (MDGs) that include a 30% reduction in LBW by the year 2025.1,6 These goals have brought attention to South Asia as about half of all LBW infants are born in India and Bangladesh
The results from this study suggest that high maternal Hgb concentration (. 13 g/dL) is associated with a 2-fold increase in risk of LBW

Summary

Introduction

Low birth weight (LBW) continues to be a pressing global health concern as approximately 20 million babies are born each year with a weight of , 2,500 grams.[1]. In 2012, the WHO set global nutrition targets under the Millennium Development Goals (MDGs) that include a 30% reduction in LBW by the year 2025.1,6 These goals have brought attention to South Asia as about half of all LBW infants are born in India and Bangladesh. National LBW surveys conducted in Bangladesh in 2003–2004 and again in 2015 document significant progress in reducing the incidence of LBW in the region from 36% in 2003–2004 to 22.6% in 2015.3 This progress has been attributed to improvement in socioeconomic conditions and widespread implementation of routine iron-folate supplementation.[3] Despite this progress, further work is needed to reduce LBW in South Asia to a rate comparable with the 6% of all births seen in many developed nations.[3,6]

Methods

Results

Discussion

Conclusion