en Effect of Virtual Reality-based Health Education on the Prevention of Gestational Diabetes Mellitus in Pregnant Women in the First Trimester Aims: This study investigated the impact of virtual reality-based health education on preventing gestational diabetes mellitus among first-trimester pregnant women in South Kalimantan, Indonesia. Materials & Methods: This pre-experimental study, using a one-group pre-post-test design, was conducted on 120 respondents who were selected through accidental sampling. Participants completed a structured questionnaire to assess their knowledge of gestational diabetes mellitus prevention. The questionnaire underwent a validation process involving expert reviews and a pilot test with 30 participants, resulting in a content validity index of 0.85, indicating strong agreement among experts. Data analysis was performed using SPSS 21 software, employing the Wilcoxon signed-rank test at a significance level of Î±=0.05. Findings: There was a significant improvement in knowledge levels post-intervention. The mean knowledge score increased from 13.75Â±3.2 before the intervention to 18.20Â±2.9 after the intervention, reflecting a percentage increase of 49.6%. The Wilcoxon test result (p=0.0001) and the effect size of 1.56, indicated a large effect of virtual reality-based health education on improving knowledge about gestational diabetes mellitus prevention among participants. Conclusion: Virtual reality-based health education effectively increases pregnant womenâ€™s knowledge about preventing GDM. Virtual Reality,Gestational Diabetes,Health Education, 89 94 http://daneshafarand.org/browse.php?a_code=A-10-78676-8&slc_lang=en&sid=4