記住我
Abstract
Introduction: Maternal stress responses play an important role in the etiology of fetal and maternal disorders other than biomedical risks. The surge of emergency evidence that yoga as adjuvant therapy can have significant beneficial effects in the prenatal period and in the fetus. Aim: The aim of this study was to evaluate the immediate effect of Pranava Pranayama on maternal and fetal cardiovascular parameters. Materials and Methods: Three-way cross-over study was done on 3 consecutive days in 60 pregnant women (3rd trimester) with 10 min of breath awareness, listening to OM, and performing Pranava Pranayama. Maternal heart rate (MHR) and systolic and diastolic pressures were measured before and after each session, and cardiovascular indices were derived with formulae. Fetal heart rate (FHR) was obtained from nonstress test tracing. Data were assessed using GraphPad InStat version 3.06. Student's t-test was used for intragroup comparisons while repeated measured ANOVA with Tukey–Kramer multiple comparison tests were done for intergroup comparison. Results: Significant changes (P < 0.001) were found in MHR and FHR immediately after all three interventions. Delta% changes showed the greatest fall in MHR (P = 0.03) after Pranava as compared to the other two while in FHR, both OM group and Pranava were significant (P < 0.001). Conclusion: There were significant changes found in MHR, FHR, and cardiovascular responses rate-pressure product and double product after a single session of intervention. Yogic breathing techniques Pranava may enhance cardiovascular hemodynamics of the maternal–fetal unit. Reduction in maternal and fetal cardiovascular parameters attributed to reduced sympathetic activity coupled with enhanced vagal parasympathetic tone. Such changes in cardiac autonomic status may enhance placental circulation and lead to healthier fetal development.
Keywords: Fetal heart rate, Pranava, pranayama, pregnancy
How to cite this article: Introduction 
Pregnancy is the phase in human life where two individuals are physiologically interlinked; the prenatal condition represents a unique opportunity to investigate the physiological interaction between two individual organisms. With respect to cardiac interaction, there is evidence that indicates an influence of the maternal condition on fetal heart rate (FHR), which is a vital predictor of fetal outcome.[1],[2],[3] There are studies that suggest sukha pranayama (slow and deep breathing) at the rate of 6 breaths/minute can reduce heart rate (HR) and blood pressure (BP) in hypertensive patients within 5 min of practice, and may be due to a normalization of autonomic cardiovascular rhythms as a result of increased vagal modulation and or decreased sympathetic activity and improved baroreflex sensitivity.[4]
The human fetus is capable of responding to a sound stimulus applied to the maternal abdomen, by an increase in movement of the fetal muscles. The response becomes more marked as the term approaches. There are studies that proved the development of such a response may furnish some index of the development and maturity of the fetus.[5] Maternal stress and anxiety during pregnancy affect the fetus's developing brain morphology and child development outcomes.[6]
It is hypothesized that maternal stress responses affect the fetus by reducing blood flow and oxygen to the uterus and increases activation of the placental stress system, resulting in the circulation of the corticotrophin-releasing hormone.[7] Maternal stress plays an important role in the etiology of fetal and maternal disorders other than biomedical risks.[8] Yoga practices may moderate stress responses at the physiological level that would impact both maternal and fetal outcomes.[9] It is anticipated that there will be positive improvements in all study parameters after adjuvant yoga therapy. Yoga is understood as the re-integrator of the multicomplex, inducing a state of dynamic well-being a state of health.[10] The importance of this study is, it will pave way for the application of yoga therapy in pregnant women and enable the determination of wellness and bonding between pregnant mothers and their fetuses.
Materials and Methods This study was undertaken as an interdisciplinary collaborative work between the Centre for Yoga Therapy, Education and Research (CYTER) of Sri Balaji Vidyapeeth (SBV), and the Department of Obstetrics and Gynecology (OG) of Mahatma Gandhi Medical College and Research Institute, Puducherry. Approval was obtained from the Institutional Research Council of MGMC and RI, and the Institutional Human Ethics Committee of SBV University Project No: PG Dissertation/2018/06/03 dated 06/06/2018. The study has also been registered on the Clinical Trial Registry-India (CTRI: CTRI/2018/08/015163).
The subjects for the study were referred from the OG inpatient department of MGMCRI. Seventy-one pregnant women who had completed 28 weeks of gestation were assessed and 60 out of them who satisfied the inclusion criteria were recruited for the study and the remaining 11 were excluded from the study. Pregnant women in whom baseline FHR can be assessed, those who are willing to participate, and above 18 years of age were included in the study. Those who have medical or surgical OG complications, elderly pregnant women and high-risk pregnancies, who cannot and are not willing to perform yoga practice, and those in whom FHR cannot be assessed and are already regular practitioners of yoga were excluded from the study. Convenience sampling method was followed, and as the subjects belonged to a vulnerable population, the study was clearly explained and informed consent was received from all the 60 recruited subjects [Figure 1].
Single session pre–post comparison was done with a three-way cross-over study design that was conducted in 60 pregnant women in their third trimester. Three interventions were randomized and sequenced by three ways three periods cross-study design. The techniques (A: Breath Awareness, B: Listening to OM, and C: Performing Pranava Pranayama) were given to pregnant women in the antenatal ward on 3 consecutive days for 10 min each day [Table 1].
Cardiovascular parameters, namely maternal heart rate (MHR), systolic pressure (SP), and diastolic pressure (DP), were measured before and after the session, and rate-pressure product (RPP), double product (DoP), mean pressure (MP), and pulse pressure (PP) derived with the formulae.[4] FHR was derived from the nonstress test (NST) tracing.
The study participants were asked to sit in a comfortable semi-recumbent posture with legs stretched forward, with interlocked fingers and hands over the abdomen in their comfort level without straining themselves, and then were advised to be aware of their breath and follow the instructions.
The control period and interventions were done as follows.
Control (breath awareness)
The subjects were asked to be consciously aware of and “watch” their own breathing pattern in a neutral manner for 10 mts.
Listening to OM chanting
The subjects were asked to listen by headphones to “OM Chanting” done by Dr. Ananda Balayogi Bhavanani and were asked to be aware of fetal movement for 10 mts.[11]
Chanting Pranava Pranayama (Pranava)
They were asked to slowly breathe in and out through the nostrils at their comfortable level without straining themselves, and then were advised to follow the instructions:
Slowly breathe in deeply (as per individual subject's limitation) and on exhalation slowly chant Akara (AAAA…), be aware of the vibration and fetal movements. Repeat two more rounds of practiceSlowly breathe in deeply (as per individual subject's limitation) and on exhalation slowly chant Ukara (UUU…), be aware of the vibration and fetal movements. Repeat two more rounds of practiceSlowly breathe in deeply (as per individual subject's limitation) and on exhalation slowly chant Makara (MMM…), (as per individual subject's limitation). Repeat two more rounds of practice.[10]Each round of practice is followed by a minute of silence. During practice, the subjects were asked to be aware of their breath and fetal movement.
To ensure objectivity, the MHR and BP were recorded before and after 10 min of intervention, and data were measured by qualified nurses in the OG ward using a noninvasive semi-automatic BP monitor (CH-432, Citizen Systems, Tokyo, Japan) with an instrumental accuracy of ±5% for HR and ±3 mm Hg for BP.
PP is the difference between SP and DP, represents the force generated by the contraction of the heart, and is measured by millimeters of mercury (mmHg). PP = SP-DP[12]MP is the average BP in an individual during a single cardiac cycle, and is calculated by the formula, MP = DP + 1/3 PP[13]RPP is the hemodynamic response to determine the myocardial oxygen consumption with units of HR and SP. RPP = (HR × SP)/100[4]DoP is the hemodynamic response to determine the myocardial oxygen consumption with units of HR and MP. DoP = HR × MP[14]FHR tracing is recorded by the NST instrument. It is a simple noninvasive test in pregnancies over 28th-week gestation; the test involves attaching one belt to the mother's abdomen to measure FHR and another belt to measure contractions. Movement, FHR, and “reactivity” of HR to movement are measured for 20–30 min.[15]Statistical analysis
Data were assessed using GraphPad InStat version 3.06 for Windows 95 (GraphPad Software, San Diego California USA, www.graphpad.com). Student's t-test was used for intragroup comparisons for passing normality testing. Repeated measures of ANOVA with the Tukey–Kramer Multiple comparison tests were used for intergroup comparison. P < 0.05 was accepted as indicating significant differences between means.
Results The study evaluated the immediate effect of maternal and fetal cardiovascular parameters. The cardiovascular changes after the intervention were evident in this study between the control (breath awareness) group and the two intervention groups – OM and Pranava [Table 2].
Table 2: Comparison of maternal and fetal cardiovascular parameters with intervention in 60 pregnant womenThere were significant changes in MHR and FHR immediately after a single session of breath awareness, OM, and Pranava (P < 0.001). The cardiovascular response with regard to RPP and DoP was more significant immediately after a single session of breath awareness, OM, and Pranava. Although there was no significance both in SP and DP, whereas the OM group shows close to significance (P = 0.059). The MP decreased significantly following OM (p = <0.024). Delta % changes during Pranava showed a greater fall in MHR (P = 0.03) compared to OM and breath awareness. Both FHR and MHR showed highly significant delta % changes in the OM group (P < 0.001). The FHR response was more significant (P < 0.001) in both OM and Pranava. Mothers experienced more fetal activity while listening to OM and chanting Makara phase (Mmmm) in Pranava.
Discussion The present study was planned since there was a surge of emergency evidence that yoga as adjuvant therapy can have significant beneficial effects in the prenatal period and in a fetus. In the human life cycle, there is no time when two individuals are physiologically intertwined than in the period before birth. The prenatal condition represents a unique opportunity to investigate the physiological interaction between two individual organisms. With respect to cardiac interaction, there is evidence that indicates an influence of the maternal condition on FHR. All major organs are formed in the fetus, but they continue to grow and develop during this period.
In this study, the immediate effect of Pranava Pranayama along with passive listening to OM chanting and a control period of breath awareness was evaluated on maternal cardiovascular parameters and FHR in 60 pregnant women.
The cardiovascular changes immediately after the study were evident in this study between the control group (breath awareness), and the OM and Pranava intervention groups [Table 2]; implying better autonomic regulation of the heart in the subjects. A previous study on how slow deep breathing shifts the autonomic nervous system concluded that the mechanical stretching during inhalation and exhalation generates inhibitory signals and hyperpolarizing current in the central and peripheral nervous systems and surrounding tissues which shift the autonomic balance to parasympathetic dominance.[16] During all three techniques, there was a significant fall in MHR and FHR, the RPP and DoP are indirected indicators of myocardial oxygen consumption and load on the heart and reduces the strain on the maternal heart.[17] RPP is inversely propositional to heart rate variability (HRV), sympathetic activation increases HR and RPP, and decreases HRV and hence, implies improved cardiac autonomic regulation. Reduction in HR results in fall of SP which in turn attribute to the reduction in cardiac output due to a decrease in venous return. Increased vagal modulation of sinoatrial and atrioventricular nodes along with enhancement of baroreceptor sensitivity also decreases MHR. As there is a connecting link between the mother and the fetus, there was a reduction in FHR.
In a previous study by Dietz et al. reported that HRV is a noninvasive and surrogate marker to determine fetal overall health and the development of fetal autonomic nervous system and influenced by maternal behavior.[3] Maternal psychological variables may shape the neurobehavioral development of the fetus and it has been suggested that the pregnant mother's acute emotional reactivity can influence FHR patterns and that a stress-induced increase in maternal BP is not the primary signal by which a women's stress response is transduced to her fetus.[18]
While performing Pranava Pranayama, there showed an increase in MP compared to other interventions pointing out toward the possibility of difficulty due to the gravid uterus there increasing the workload of the heart. Hence, it is advised that hypertensive mothers should be careful while performing Pranava pranayama, whereas during listening to OM pregnant women felt more relaxed.
Gerhardt and Abrams reported evidence of fetal exposure to sound and vibroacoustic stimulation.[19] The fetus receives various forms of maternal stimulation across gestation such as the mother's voice, the vibration of diaphragmatic movement, and synchronize with her voice, these are the key aspects of normal fetal growth and development. Chapman reported findings related to the effect of exposure to maternal voice, the infants exposed to maternal voice (34/50) demonstrated a gross motor pattern of laterality than lullaby (29/50). This was a positive indication of preterm development.[1] This flashed light on our point why there was more fetal activity on listening to OM and on chanting Makara phase of Pranava.
Previous studies by Bhavanani et al. reported that Pranava Pranayama and relaxation are effective in reducing blood pressure and stress.[20],[21] It was studied in hypertensive and diabetic patients and found to reduce HR and SP within 5 min of the practice as well as reduce stress and anxiety over 12 weeks of training. This was attributed to the normalization of autonomic cardiovascular rhythms as a result of increased vagal modulation and/or decreased sympathetic activity and improved baroreflex sensitivity. Effects of Pranava relaxation in the supine position are strikingly similar to the deep relaxation technique (DRT) popularized by SVYASA University, Bangalore and several studies have reported that DRT improves sustained attention and reduces the state of anxiety while reducing cardiac sympathetic activity.[22],[23]
Limitations
The present study is limited by the smaller sample size and the fact that the protocol was not validated by external experts though it was being routinely used at CYTER of SBV. It was also limited to a single center. Further, multicentric studies that explore functional changes with correlations between such changes and other biochemical markers may deepen the understanding of intrinsic mechanisms by which these changes are occurring in yoga therapy programs.
Conclusion It may be concluded from the present study that yoga has therapeutic and palliative effects during the prenatal period. It seems to regulate difficulties due to a gravid uterus such as leg pain and sleep disturbances. Significant changes were found in MHR, FHR and cardiovascular responses, RPP and DoP indicating lower oxygen consumption and decreased load on the heart thereby enhancing maternal cardiovascular efficiency. The decrease of MP following OM maybe attributed to the fall in SP and MHR while listening to OM and Pranava Pranayama seemed more significant in normalizing FHR. Mothers experienced increased fetal activity both while listening to OM as well as during the chanting of Makara phase (Mmm.) in Pranava Pranayama. Pregnant women felt more relaxed and comfortable while listening to OM and were able to feel the bonding with the fetus while performing Pranava pranayama. Yoga as therapy is cost-effective, relatively simple, and carries minimal risk and hence could be advocated as an adjunct complementary therapy for promoting health and well-being. This by default also influences fetal well-being by possibly enhancing placental circulation, leading to healthier fetal development. Hence, it may be recommended as an adjuvant therapeutic modality in routine antenatal care in medical institutions.
Ethical clearance
Institutional Human ethics committee of SBV University project No: PG Dissertation /2018/06/03 dated 06/06/2018.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References 
Correspondence Address:
Ananda Balayogi Bhavanani
Institute of Salutogenesis and Complementary Medicine, Sri Balaji Vidyapeeth, Pillayarkuppam, Puducherry - 607 402
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ijoy.ijoy_151_22
留言 (0)