1 Vol.:(0123456789) Scientific Reports | (2024) 14:4399 | https://doi.org/10.1038/s41598-024-54248-w www.nature.com/scientificreports Determinants of low birth weight among newborns delivered at Mettu Karl comprehensive specialized hospital, southwest Ethiopia: a case–control study Samuel Ejeta Chibsa 1* , Mustafa Adem Hussen 1 , Kenbon Bayisa 1 & Bilisumamulifna Tefera Kefeni 2 Low birth weight is a newborn delivered with birth weight of less than 2500 g regardless of gestational age is called. It is a significant issue affecting over 30 million infants worldwide. Thus, the study determine factors associated with low birth weight among newborns delivered at Mettu Karl Comprehensive Specialized Hospital, Southwest Ethiopia. A facility-based case–control study was conducted with 336 newborns (112 cases and 224 controls) from September 12 to December 23, 2022. The study population was newborns with birth weights of 2500 g to 4000 g as controls and newborns with birth weights < 2500 g were cases. Simple random sampling techniques were used to recruit study participants with a ratio of 1 to 3 cases to controls, respectively. Data was collected by interviews and a checklist. Data were entered and analysed using SPSS version 23. Binary and multivariate logistic regression analyses were computed to identify factors associated with low birth weight, a p-value less than 0.05 was used to declare the strength of statistical significance. A total of 327 newborns were contacted, yielding a 97% response rate. MUAC < 23 cm (AOR = 2.72, 95% CI 1.24 to 6.19), inadequate diet diversification (AOR = 4.19, 95% CI 2.04 to 8.60), lack of iron and folic acid supplementation (AOR = 2.94, 95% CI 1.25 to 6.88), history of hypertension (AOR = 2.55, 95% CI 1.09 to 6.00), and lack of nutritional counselling (AOR = 4.63, 95% CI 2.22 to 9.64) were determinants of low birth weight. Low birth weight is linked to residence, maternal MUAC, hypertension history, and ANC visit. Lifestyle modifications, early detection, management, and nutrition information can reduce risk. Keywords Newborn, Low birth weight, Mettu, Ethiopia Low birth weight (LBW) is a baby delivered with a birth weight of less than 2500 g (5.5 pounds), regardless of gestational age 1 . A large group of infants are born preterm, intrauterine growth-restricted, or both preterm and intrauterine growth-restricted 1,2 . Birth weight is a predictor of perinatal and infant survival, morbidity and mortality, and later risk for developmental disabilities in their lives 3,4 Globally, more than 30 million newborns are delivered annually; of this, almost one-quarter of them have low birth weight 1 . e majority of births occur in south-central Asia, with one-third of them weighing less than 2500 g 4,5 . Low birth weight: in Sub-Saharan Africa, 15 percent of them grow up as stunted children, developing different complicated infections that require later hospital admission 3,6 . Low birth weight is primarily determined by maternal health condition and nutrition status in developing countries, unlike in developed countries, where usually cigarette smoking during pregnancy is the primary cause of low birth weight 7 . Additionally, genetic, socio-demographic, maternal medical illness, intrauterine fetal com- plications, and environmental factors are predictors of low birth weight across the world 6,8 . In Ethiopia, low birth weights ranged from (10.4 to 17.3%) and this makes Ethiopia grouped under five countries that are accountable for half of global neonatal deaths among Sub-Saharan Africa 9–11 . e World Health Organisation is set to reduce the burden of low birth weight by as little as 30% by 2025 through nutritional policies on getting affordable, accessible, and appropriate health care for preventing and OPEN 1 Midwifery Department, College of Health Science, Mattu University, Mettu, Ethiopia. 2 Public Health Department, College of Health Science, Mattu University, Mettu, Ethiopia. * email: samejeta09@gmail.com