Determinants of low birth weight among newborns in selected public hospitals in Southwest Ethiopia: a multi-center unmatched case-control study

Low Birth Weight (LBW), defined as a birth weight below 2500 g, remains a major public health problem in Africa, including Ethiopia, where existing evidence is limited by narrow geographic and cultural coverage. This study aimed to identify determinants of LBW among newborns in public hospitals across Southwest Ethiopia. A multi-center, facility-based, unmatched case-control study was conducted among LBW cases and controls with normal birth weight (1,2 ratio) recruited from three public hospitals. Eligible newborns were live, singleton births; those with congenital anomalies, born to diabetic mothers or born to critically ill mothers were excluded. Data were collected using structured questionnaires, face-to-face interviews, medical record review, and maternal anthropometric measurements, then entered into Epi-Info 7.2.6.0 and analyzed in SPSS 27. Variables with p < 0.25 in bivariate analysis were included in multivariable logistic regression; significance was set at p < 0.05. A total of 400 participants (133 cases and 267 controls) were included, with a 100% response rate. Independent predictors of low birth weight were lack of nutritional counseling [AOR = 5.36, 95% CI (3.18-9.06)], maternal anemia [AOR = 2.03, 95% CI (1.17-3.53)], incomplete antenatal visits [AOR = 3.51, 95% CI (1.90-6.49)], not taking additional meals during pregnancy [AOR = 1.78, 95% CI (1.06-2.98)], and poor iron-folate adherence [AOR = 1.93, 95% CI (1.14-3.28)]. Inadequate nutritional counseling, anemia, incomplete antenatal visits, lack of additional meals, and poor iron-folate adherence were determinants of low birth weight. Health facilities, government officials, and policymakers should consider these factors when designing maternal programs.