Low birth weight has significant etiologic heterogeneity. Risk factors that impact gestational age and fetal growth patterns among LBW infants are not well understood.Using the National Vital Statistics System birth data (2014–2023), we developed log-binomial regression models to estimate the adjusted risk ratios for determinants of LBW for the subgroups preterm birth and small for gestational age. LBW was associated with multiple factors, but they varied by the underlying leading factors PTB and SGA. Significant associations for preterm infants with LBW were biological conditions like eclampsia (RR = 1.2, 95%CI = 1.18-1.22) and plurality (RR = 1.5, 95%CI = 1.47 -1.48). Among SGA infants with LBW, pre-pregnancy risk factors such as previous PTB (RR = 1.6, 95%CI = 1.61-1.66) and pre-pregnancy BMI (RR = 1.2, 95%CI = 1.14-1.18) were significant. Distinct determinants influence LBW among different birth pathways, such as PTB and SGA varying in their risk factors.