Introduction: Anxiety is a response to an unclear and ambiguous threat; in other words, anxiety is an unpleasant feeling of unease and distressing fear from the anticipation of a threat whose origin is unknown. Marx and Leader , after reviewing 22 studies conducted in this field, estimated that approximately 3% of the general population suffers from anxiety. The present study aimed to compare the effectiveness of Jacobson's progressive muscle relaxation (PMR) therapy and Jon Kabat-Zinn's mindfulness-based stress reduction (MBSR) therapy on pregnancy-related anxiety in primiparous women

Materials and Methods: The present study followed a quasi-experimental approach with a pretest-posttest design and a control group with a one-month follow-up period. The statistical population included all pregnant mothers in Neyshabur City, Iran, who had referred to health-treatment centers in the last three months of 2024. The sample consisted of 45 people who were selected conveniently and placed in two experimental groups and a control group (15 people in each group). The intervention groups received Jacobson's PMR therapy for four sessions and Jon Kabat-Zinn's MBSR therapy for eight 90-minute sessions twice a week. Data were collected using the Vandenberg Pregnancy Anxiety Scale and analyzed using a mixed repeated measures analysis of variance (ANOVA).
Results: The results indicated that there was a significant difference between the experimental and control groups; both treatments reduced pregnancy-related anxiety scores in primiparous women (p<0.05). According to the results, the mean pregnancy-related anxiety scores in the MBSR group were 46.17 and standard deviation 5.943 compared to the mean pregnancy-related anxiety in the control group of 85.70 and standard deviation 7.861, which was significantly lower than the mean pregnancy-related anxiety scores in the PMR group of 65.65 and standard deviation 6.047 compared to the mean pregnancy-related anxiety in the control group of 85.70 and standard deviation 7.861 (p<0.05), indicating greater effectiveness of MBSR compared to PMR.
Conclusion: The results demonstrated that both PMR and MBSR were effective in reducing anxiety in primiparous women; however, MBSR was more effective. These findings have the potential to be implemented in clinical settings such as women's clinics, pregnancy counseling centers, and even online programs.