Maternal hemoglobin and risk of low birth weight: A hospital-based cross-sectional study in Nepal

Maternal hemoglobin during pregnancy is an important predictor of neonatal outcomes such as birth weight. The newborn weight of an infant is considered a crucial factor for morbidity and mortality. This study aimed to assess the association between maternal hemoglobin concentration and newborn weight at term pregnancy.

A hospital-based cross-sectional study was conducted at Tribhuvan University Teaching Hospital (TUTH), Kathmandu, Nepal from 14^th April 2018 to 13^th April 2019. Term singleton pregnant women who were admitted for delivery in the labor room of TUTH were included in this study. Maternal characteristics such as age, parity, birth space, ethnicity, education level, dietary habit, body mass index (BMI), and hemoglobin level were recorded. The newborn weight was taken immediately after delivery. The main outcome of this study was the birth weight. The association between hemoglobin level and newborn weight was analyzed using bivariate and multivariable logistic regression analysis.

Of 2,418 term pregnant women, the prevalence of low hemoglobin and high hemoglobin levels were 24% (95% CI: 22-25.4), and 17% (95% CI: 15.7-18.7), respectively. The prevalence of low birth weight (LBW) was 12.9% (95% CI: 11.7-14.4). Multivariable logistic regression analysis showed that those mothers who had low hemoglobin concentration (adjusted Odds Ratio/aOR = 3.77, 95% CI: 2.84-5.01), and high hemoglobin concentration (aOR = 3.07, 95% CI: 2.23-4.24) had higher odds of having LBW compared to mothers having normal hemoglobin level. Mothers with both young age pregnancy (aged 16-20 years) and older pregnancy (aged ≥31 years) (aOR = 1.60, 95% CI: 1.01-2.52) and (aOR = 1.60, 95% CI: 1.06-2.41), respectively had higher odds of LBW compared to mothers aged 21-25 years. Those mothers who attended a primary level of education had higher odds of (aOR = 1.93, 95% CI: 1.05-3.55) LBW compared to those mothers with a higher level of education. Moreover, mothers who belonged to Janajati ethnic group (aOR = 0.47, 95% CI: 0.34-0.65) compared to the Brahmin/Chhetri ethnic group, and mothers with a birth space of more than three years (aOR = 0.63, 95% CI: 0.41-0.97) compared to those who had less than three years of birth spacing and mothers who were overweight/obese (aOR = 0.74, 95% CI: 0.55-0.99) compared to normal nutritional status had lower odds of having LBW.

Our study concludes that both low and high hemoglobin had an increased risk of having low birth weight. Policies and programs can benefit by adopting the findings of this study. More empirical research is critical to understanding the impact of hemoglobin levels on birth weight.