The Effects of Heart Rate Variability Biofeedback-Assisted Stress Management Training on Pregnant Women and Fetal Heart Rate Measures
Janice E. Keeney, B.A., M.Ed., LPC, BCIAC
Ph.D. Dissertation, University of North Texas, 2008.
This study examined effectiveness of heart rate variability (HRV) biofeedbackassisted stress management training in reducing anxiety and stress in pregnant women and the effect of maternal stress management skills practice on fetal heart rate measures in real time. Participants were seven working pregnant women who volunteered in response to recruitment announcements and invitations from cooperating midwives. Reported state and trait anxiety and pregnancy specific stress were measured during five 45 to 50 minute training sessions. Training included bibliotherapy, instruction in the use of emotion-focused stress management techniques, and HRV biofeedback. Subjects used portable biofeedback units for home practice and were encouraged to practice the skills for 20 minutes a day and for short periods of time during stressful life events. At the end of training, fetal heart rate was monitored and concurrent maternal HRV measures were recorded.
Repeated measures ANOVA and paired samples t-test analysis of study data revealed no statistically significant reductions in state or trait anxiety measures or in pregnancy specific stress measures. Partial eta squared (η2) and Cohen’s d calculations found small to medium effect sizes on the various test scales. Friedman’s analysis of variance of biofeedback measures showed a statistically significant decrease in low HRV coherence scores (χ2 = 10.53, p = .03) and medium HRV coherence scores (χ2 = 11.58, p = .02) and a statistically significant increase in high HRV coherence scores (χ2 = 18.16, p = .001). This change is an indication of improved autonomic function. Results of concurrent maternal and fetal HRV recordings were generally inconclusive. A qualitative discussion of individual subject results is included. During follow-up interviews five subjects reported that they felt they were better able to cope with stress at the end of the study than at the beginning, that they used the stress management skills during labor, and that they continue to practice the skills in their daily lives.