AimThe present study aimed to examine the effects of a mindfulness‐based stress reduction (MBSR) program and deep relaxation exercises on pregnancy‐related anxiety levels.Materials and MethodsThis randomized parallel‐group controlled trial was conducted with 95 pregnant women (MBSR: n = 32, deep relaxation exercises: n = 31, control: n = 32) between 1 August and 15 October 2022 with pregnant women who were registered at the pregnancy outpatient clinics of a hospital in the Southeastern Anatolia Region of Türkiye. CONSORT guidelines were followed in our study. The participants in the MBSR group were given an eight‐session MBSR program, consisting of two sessions per week for 4 weeks, whereas the participants in the deep relaxation exercises group were asked to do exercises at home with deep relaxation videos four times a week for 4 weeks. The participants in the control group received only routine prenatal care.ResultsThe mean PRAQ‐R2 Fear of Giving Birth subscale scores of the participants in the MBSR and deep relaxation exercises groups after the intervention were lower than that of the participants in the control group. Additionally, the mean total PRAQ‐R2, PRAQ‐R2 Worries about Bearing a Physically or Mentally Handicapped Child subscale and PRAQ‐R2 Concern about One's Own Appearance subscale scores of the participants in the MBSR group were found to be significantly lower than the scores of those in the deep relaxation exercises and control groups (p < 0.001).ConclusionThe MBSR program is an effective method for reducing pregnancy‐related anxiety levels. Additionally, deep relaxation exercises are alternative practices for reducing the fear of giving birth among pregnant women.Trial registration: NCT05447000