Assessment of Undernutrition Among Under 5 Children in Developing Countries: A Systematic Review and Meta‐Analysis

ABSTRACT Background and Aim Undernutrition is gradually declining worldwide except in sub‐Saharan Africa and parts of South Asia. Prevalence is almost stagnant in low‐and middle‐income countries (LIMCs), contributing to child mortality and disease burden. To systematically review existing literature and conduct a meta‐analysis to estimate the prevalence of childhood undernutrition—specifically stunting, wasting, and underweight—and identify associated factors among children under five in developing countries. Methods Following PRISMA 2020 guidelines, this study systematically reviewed literature from 2010 to 2022 across PubMed, Scopus, Cochrane Library and Web of Science on developing countries. Study quality was assessed using JBI scores. Meta‐analyses estimated pooled prevalence and factors of undernutrition using the DerSimonian–Laird random‐effects model. Heterogeneity was assessed via I ² and Cochran's Q. Subgroup analyses by year and continent were performed for undernutrition indicators. Sensitivity analyses showed minimal discrepancies, supporting the robustness of findings. Results We included 157 studies in this research. Pooled prevalence of stunting, wasting, and underweight was 33% (95% CI: 31–35), 12% (95% CI: 11–13), and 23% (95% CI: 21–25), respectively. Subgroup analysis indicates that Asia had the highest wasting (13%, 95% CI: 11–16) and underweight (27%, 95% CI: 23–31), while Africa had the highest stunting (35%, 95% CI: 33–38. Significant heterogeneity was found across studies and continents ( p < 0.05) for each indicator. Male children had 27% (POR:1.27; 95% CI: 1.22–1.32; p < 0.05), 31% (POR:1.31; 95% CI: 1.19–1.43; p = 0.08), and 44% (POR:1.44; 95% CI: 1.18–1.6; p < 0.05) higher odds of being stunted, wasted, and underweight. Rural residence, wealth status, parental education, child age group, mother BMI, breastfeeding, birth order, unprotected water source for drinking and food‐insecure household were key undernutrition factors. Conclusion The findings underscore the need for targeted nutritional interventions addressing the identified socioeconomic and healthcare risk factors. Region‐specific strategies will be essential to sustainably reduce undernutrition.