BACKGROUND: Previous studies reported possible connections between dietary factors and pregnancy complications
however, confounders tend to confound the results. A two-sample Mendelian randomization (MR) study was carried out to explore the impact of dietary intakes on the risk of pregnancy complications. METHODS: Exposure data in this study were derived from the IEU Open GWAS project, and the outcome data were from the FinnGen study. The inverse variance-weighted (IVW) method is the main analytical method used in this study. In addition, we verified the accuracy of the findings by performing sensitivity analyses using other methods. RESULTS: After rigorous False Discovery Rate (FDR) correction, dried fruit intake can reduce the risk of ectopic pregnancy (OR [odds ratio]: 0.36, 95% CI [confidence interval]: 0.21-0.62). Fresh fruit intake was positively associated with pregnancy hypertension (OR: 2.26, 95% CI: 1.32-3.87), and cheese intake was negatively related to pregnancy hypertension (OR: 0.63, 95% CI: 0.47-0.85). In addition, cheese intake was negatively associated with pre-eclampsia (OR: 0.53, 95% CI: 0.38-0.72) and gestational diabetes (OR: 0.48, 95% CI: 0.36-0.64). There was no significant causality in this study for the analyses of other dietary intakes and pregnancy complications, and no heterogeneity or horizontal pleiotropy was found. CONCLUSIONS: Our two-sample MR study explores the causal association between dietary intakes and pregnancy complications, and our results contribute to the primary prevention of pregnancy complications. The mechanism by which dietary intakes affects pregnancy complications can be validated by further basic observational studies.