Objectives/Goals: To identify lipid signatures associated with adverse pregnancy outcomes (APOs) and postpartum weight retention (PPWR) in women entering pregnancy with overweight or obesity and to explore potential epigenetic mechanisms through ongoing DNA methylation (DNAm) analysis. Methods/Study Population: The GROWell: Goals for Reaching Optimal Wellness study was a blinded, randomized clinical trial to improve dietary support during pregnancy and postpartum. Data were collected via online questionnaires, electronic health records (EHRs), and participant-collected dried blood spots (DBS) at 10–16 weeks, 36–38 weeks, and 3 months postpartum. We analyzed DBS data from 49 participants using three lipidomic analytical techniques: weighted lipid correlation network analysis, differential lipid analysis, and partial least squares discriminant analysis. Lipid profiles were characterized and then tested for associations with APOs and PPWR at all three time points. DNAm analysis from the samples is ongoing to determine the epigenetic mechanisms associated with lipid dysregulation and pregnancy outcomes. Results/Anticipated Results: The lipid network analysis revealed positive correlations between specific lipid types and APOs, particularly at 10–16 weeks and postpartum. Notably, triglycerides and phosphatidylcholine were associated with an increased risk of APOs. Additionally, in the third trimester, triglycerides were positively correlated with weight-related variables. Postpartum analysis also showed a positive correlation between elevated triglyceride levels and a history of APOs. The network analysis also revealed positive associations between triglycerides and PPWR, which were most evident at the 36–38 week and postpartum time points. Ongoing methylation analysis is expected to identify genomic regions associated with pregnancy outcomes. Discussion/Significance of Impact: These findings underscore the significant role of lipids in pregnancy outcomes for individuals with overweight or obesity. Identifying lipidomic and methylome biomarkers of risk for APOs and PPWR may help with early detection and intervention, improving maternal and fetal health.