Environmental exposure to pesticides is widespread and commonly occurs in mixtures, and pregnant women are particularly concerned. Trimethylamine N-oxide (TMAO), a dietary-derived catabolite linked to cardiometabolic disease, may be influenced by pesticide exposure. However, limited knowledge exists regarding the associations, and studies have primarily been restricted to single pesticides. To address this gap, we examined the associations of pesticide exposure with urinary TMA, TMAO, and TMAO-to-TMA ratio among 1067 pregnant women residing in a rural area. Latent class analysis (LCA) was applied to identify distinct patterns of pesticide exposure based on urinary metabolite concentrations. Multiple linear regression (MLR) models and Bayesian kernel machine regression (BKMR) models were employed to estimate the effects of single pesticides, exposure patterns, and combined exposure. Four distinct pesticide exposure patterns were identified. Higher concentrations of pesticide metabolites were found to be associated with increased urinary TMAO levels (β: 0.043 to 0.254, < 0.05). In the MLR models for individual pesticides and exposure patterns, carbofuran phenol (CFP), pentachlorophenol (PCP), and 2-phenylphenol (OPP) exhibited positive associations with urinary TMA concentrations, while pyrethroid pesticide metabolites were correlated with the up-regulation of the TMAO-to-TMA ratio. Significant positive associations of pesticide mixtures with TMA, TMAO, and TMAO-to-TMA ratio were observed in the BKMR model, primarily driven by PCP and DCCA. Our findings provided a perspective to reveal that the mechanisms and contributions to TMAO alterations may vary among different pesticides in mixture exposure.