Objective To determine the therapeutic effect of trigonelline in early pregnancy on rats with preeclampsia (PE) induced by the nitric oxide synthase antagonist N-nitro-1-arginine methyl ester (LNAME). Methods On day zero of pregnancy, 28 Sprague - Dawley rats were randomly assigned to four groups: pregnancy control group, LNAME-induced PE group, and prophylactic use of trigonelline small dose group and high-dose group. Blood pressure and proteinuria of the pregnant rats were measured, endothelial function of pregnant rats was evaluated by femoral artery ultrasound, and the expression of inflammatory factors and endothelial-related factors were detected by ELISA. Finally, the placenta and kidney of pregnant rats were harvested for immunohistochemical analysis and to analyze the status of inflammation-related pathways by Real-time fluorescent quantitative PCR and Western blot. Results Prophylactic administration of low-dose or high-dose trigonelline improved hypertension, proteinuria, and weight loss during pregnancy, fetal growth restriction and blood flow-mediated dilation caused by LNAME. Trigonelline may act through the IκBα/ NF-κB pathway, balance endothelium-related factors and reduce inflammation activation in placenta and kidney tissues. Conclusions The preventive use of trigonelline in a PE-like rat model induced by LNAME can reduce PE symptoms, promote fetal growth, protect endothelial function and reduce inflammation.