Impaired placentation and fetoplacental hypoxia have been associated with the etiology of a number of pregnancy complications [
The word “yoga” is derived from the Sanskrit verb yuj, which means union. This refers to the union of the individual consciousness with that of the Universal Divine Consciousness that can be achieved by a wide variety of practices that range from certain postures (yoga asanas), breathing exercises (pranayama), hand gestures (mudras), cleansing exercises (kriyas), relaxation, and meditation techniques. The latter two include a wide range of practices, including visualization, guided imagery, and sound resonance practices. The rational for using these techniques requires a brief introduction on prana and its movements in the body.
The rationale for using techniques requires a brief introduction on prana and its movement in the body. According to the yogic sciences, beyond the physical body is the more subtle, pranic body, where the prana flows, and the mental body, where our thoughts are processed [
Being over 5000 years old, the science of yoga has been shown to impact a variety of physical and psychological health conditions, including anxiety, depression, metabolic syndrome, cancer, and cardiovascular, musculoskeletal, and pulmonary disorders [
Using the event ratios (0.185 in the experimental group and 0.506 in the control group) reported in a Japanese study, with
This was a randomized controlled prospective stratified single-blind trial. “Single-blind” refers to the fact that gynecologists, obstetricians, radiologists, and laboratory staff were blinded to the group selection. The trial was conducted at the Obstetric Unit of St. John’s Medical College and Hospital (SJMCH) and Gunasheela Maternity Hospital (GMH) in Bengaluru, India.
Subjects within the 12th week of gestation were approached by a research staff at the reception of the Obstetrics Department of SJMCH or GMH and introduced to the project. Those who were interested were escorted by a staff to an annex room in the outpatient department itself, where the study was explained in detail, and then were screened using a written protocol. Qualified subjects were given the opportunity to sign the informed consent form in order to complete the recruitment and begin the randomization process. We used an online random number generator by GraphPad Software (
The Ethical Committee of SJMCH provided clearance for this study and approved its informed consent form before its commencement. All participants were required to sign this consent form in order to enroll in the study.
The intervention set for each group was administered from the beginning of the 13th week to the end of the 28th week of gestation (a total of 28 sessions). The yoga group received standard care plus one-hour yoga session three times a week at the center and were instructed to practice the same routines at home. The control group received standard care plus walking for half an hour mornings and evenings (the routine antenatal exercise advised by the hospitals). The subjects in both groups were asked to keep a diary of their practices and daily physical activities, which was checked by the research staff during each of their visits to the antenatal department. The yoga classes were conducted by trained certified postgraduate yoga therapists, who used an instruction manual to conduct the classes at a reserved room within the premises of SJMCH/GMH. Standard care offered to both groups included the following: (1) pamphlets about diet and nutrition during pregnancy, (2) regular checkups by the obstetrician, and (3) biweekly follow-ups by the research staff. The purpose of these biweekly telephone follow-ups was to check if the subjects were adhering to their intervention practices and routine hospital check-ups.
The yoga intervention was selected very carefully from three categories: (1) yogic postures, (2) relaxation and breathing exercises, and (3) visualization with guided imagery. The yogic postures were chosen to reduce the physical side effects of pregnancy, such as edema, and strengthen the perineal muscles for delivery. The relaxation and breathing exercises were aimed at reducing the maternal stress. The visualization with guided imagery exercises were the backbone of this study and the rationale for their use is discussed in detail in Discussion. They were designed to test two hypotheses: (1) when attention moves in an area of the body, it causes the prana in that area also to move and (2) better movement of prana in an area of the body implies better circulation in that area. Table
Yoga interventions.
Practices1 | Duration |
---|---|
Guided relaxation with visualization and imagery | 5 min. |
Hasta āyama śvasanam (hands in and out breathing) | 1 min. |
Hastavistāra śvasanam (hands stretch breathing) | 2 min. |
Gulphavistāra śvasanam (ankles stretch breathing with wall support) | 1 min. |
Ka |
1 min. |
Guided relaxation with visualization and imagery | 5 min. |
Uttānapādāsana śvasanam (leg raise breathing) | 1 min. |
Setubandhāsana śvasanam (hip raise breathing) | 1 min. |
Pādasañcālanam (cycling in supine pose) | 1 min. |
Supta udarākar |
1 min. |
Vyāghrāsana śvasanam (tiger stretch breathing) | 1 min. |
Guided relaxation with visualization and imagery | 5 min. |
Gulphagūraṇam (ankle rotation) | 2 min. |
Jānuphalakākar |
1 min. |
Ardhātitaliāsana (half butterfly exercise) | 3 min. |
Poornātitaliāsana (full butterfly exercise) | 1 min. |
Guided relaxation with visualization and imagery | 5 min. |
Jyotitrā |
2 min. |
Nā |
2 min. |
Deep relaxation in matsyakrī |
10 min. |
Due to the importance of these visualization and guided imagery practices in this study, a brief explanation of them is warranted. In the initial visualization and guided imagery session, the subjects were asked to focus their attention on the place between the nostrils and the upper lip where the air is felt during inhalation and exhalation. In the following visualization and guided imagery sessions, the subjects were asked to visualize the fetus in the uterus and the umbilical cord connecting the fetus to the placenta. Then the participants were guided to visualize healthy blood flow from the mother’s heart into the placenta, through the umbilical cord, and bringing nourishment to the fetus.
For data analysis, PASW Statistics (formerly known as SPSS) version 18.0.3 for Mac was used. Shapiro-Wilk’s test was used to test the normality of data. For Doppler and fetal parameters with three measurements in time, repeated measures ANOVA (RM-ANOVA) was performed. However, if the difference between the baseline data of the two groups was statistically significant (fetal heart rate parameter in this study), then ANCOVA test was used, while keeping the baseline data as covariate. When there were only two measurements in time, Independent Samples
The consort diagram is presented in Figure
Consort diagram for trial profile.
A self-reported questionnaire was used to collect demographic data, which included the subjects’ age, weight, height, socioeconomics, education, and religion. The financial status of the subjects was measured in two ways: (1) subjectively, by recording the monthly household income (in Indian rupees) reported by the subjects, and (2) objectively, by having the subjects complete a socioeconomic status (SES) form, used by other Indian research groups at SJMCH, which scored the possessions and household features and produced a total score ranging from 0 to 60. These demographic data are listed in Table
Demographic data and maternal characteristics at baseline.
Groups |
|
||
---|---|---|---|
Yoga ( |
Control ( |
||
Subjects educational profile1 | |||
8th grade | 1 | 2 | |
10th grade | 7 | 5 | |
12th grade | 0 | 4 |
|
Junior college | 0 | 3 | |
Bachelor degree | 11 | 11 | |
Master degree | 5 | 4 | |
Living arrangement | |||
Independent2 | 13 | 13 | |
With parents | 8 | 13 |
|
With relatives or friends | 3 | 3 | |
Religion | |||
Hindu | 20 | 22 | |
Moslem | 0 | 2 |
|
Christian | 4 | 5 | |
Age | |||
Mean (SD) | 27.2 (4.8) | 27.5 (5.5) |
|
95% CI | 25.1–29.2 | 25.4–29.5 | |
Household monthly income3 | |||
Mean (SD) | 35.4 (28.9) | 36.9 (36.4) |
|
95% CI | 22.9–47.8 | 22.8–51.0 | |
Socioeconomic4 | |||
Mean (SD) | 35.4 (7.8) | 36.5 (9.4) |
|
95% CI | 32.1–38.7 | 32.9–40.0 | |
Maternal weight (kg) | |||
Mean (SD) | 61.8 (13.0) | 62.7 (14.6) |
|
95% CI | 56.4–67.3 | 57.1–68.3 | |
Maternal height (m) | |||
Mean (SD) | 1.57 (0.05) | 1.58 (0.06) |
|
95% CI | 1.55–1.59 | 1.55–1.59 | |
Maternal BMI | |||
Mean (SD) | 25.1 (4.8) | 25.4 (4.9) |
|
95% CI | 23.1–27.1 | 23.5–27.2 | |
Maternal systolic BP | |||
Mean (SD) | 108.3 (12.9) | 104.1 (8.3) |
|
95% CI | 102.7–113.9 | 100.9–107.3 | |
Maternal diastolic BP | |||
Mean (SD) | 67.5 (9.5) | 64.2 (7.6) |
|
95% CI | 63.4–71.6 | 61.3–67.1 |
2Independent: lived with her husband and children, if any.
3Family’s monthly income in thousands of Indian rupees as reported by the subject.
4Socioeconomic status: measured by a standard questionnaire.
a
b
c
The ultrasound fetal measurements are shown in Table
Ultrasound fetal measurements between groups.
Parameters | Gestational age | Mean ± SD |
| |
---|---|---|---|---|
Yoga ( |
Control ( | |||
Biparietal diameter (BPD) | 12th wk | 20.2 ± 4.0 | 19.5 ± 2.4 |
|
20th wk | 50.6 ± 5.4 | 46.9 ± 2.4 | ||
28th wk | 72.5 ± 2.9 | 70.4 ± 2.3 | ||
|
||||
Head circumference (HD) | 12th wk | 75.4 ± 9.4 | 74.3 ± 8.6 |
|
20th wk | 181.0 ± 7.9 | 173.7 ± 7.9 | ||
28th wk | 268.6 ± 8.7 | 262.4 ± 8.2 | ||
|
||||
Abdominal circumference (AC) | 12th wk | 62.3 ± 8.5 | 60.7 ± 6.2 |
|
20th wk | 150.0 ± 10.6 | 149.1 ± 8.9 | ||
28th wk | 243.7 ± 13.9 | 236.4 ± 11.1 | ||
|
||||
Femur length (FL) | 12th wk | 9.2 ± 1.9 | 9.3 ± 1.7 |
|
20th wk | 33.1 ± 2.1 | 31.5 ± 1.9 | ||
28th wk | 55.0 ± 2.6 | 53.0 ± 2.3 | ||
|
||||
Heart rate (HR) | 12th wk | 163.5 ± 9.4 | 157.8 ± 9.4 |
|
20th wk | 149.3 ± 7.6 | 143.0 ± 9.9 | ||
28th wk | 145.0 ± 11.6 | 141.3 ± 7.2 | ||
|
||||
Estimated fetal weight (EFW) | 12th wk | 0.065 ± 0.02 | 0.066 ± 0.01 |
|
20th wk | 0.362 ± 0.05 | 0.329 ± 0.04 | ||
28th wk | 1.275 ± 0.15 | 1.188 ± 0.13 |
aANCOVA keeping the baseline data as covariate.
Remarks: significant improvement was observed in all fetal parameters except for AC, which was near significance.
Systolic over diastolic ratio (S/D ratio), pulsatility index (PI), resistance index (RI), and diastolic notch were measured in right and left uterine arteries at the 12th, 20th, and 2nd weeks of gestation. These results are listed in Table
Measures of uteroplacental circulation between groups.
Arteries | Gestational age | Mean ± SD or count (%) |
|
||
---|---|---|---|---|---|
Yoga ( |
Control ( | ||||
Right uterine artery | Systolic/diastolic ratio | 12th wk | 3.2 ± 1.4 | 3.1 ± 1.1 |
|
20th wk | 2.3 ± 0.4 | 2.7 ± 1.1 | |||
28th wk | 2.0 ± 0.3 | 2.4 ± 0.7 | |||
Pulsatility index | 12th wk | 1.4 ± 0.5 | 1.4 ± 0.5 |
| |
20th wk | 0.8 ± 0.2 | 1.0 ± 0.5 | |||
28th wk | 0.7 ± 0.1 | 0.9 ± 0.4 | |||
Resistance index | 12th wk | 0.65 ± 0.1 | 0.64 ± 0.1 |
| |
20th wk | 0.52 ± 0.1 | 0.58 ± 0.1 | |||
28th wk | 0.46 ± 0.1 | 0.55 ± 0.1 | |||
Diastolic notch | 12th wk | 7 (22.6%) | 7 (18.4%) |
| |
20th wk | 2 (6.1%) | 3 (7.9%) |
| ||
28th wk | 1 (3.6%) | 1 (2.9%) |
| ||
|
|||||
Left uterine artery | Systolic/diastolic ratio | 12th wk | 3.5 ± 1.5 | 3.6 ± 1.6 |
|
20th wk | 2.1 ± 0.3 | 2.6 ± 1.1 | |||
28th wk | 1.9 ± 0.3 | 2.3 ± 1.2 | |||
Pulsatility index | 12th wk | 1.5 ± 0.6 | 1.5 ± 0.8 |
| |
20th wk | 0.8 ± 0.2 | 1.0 ± 0.5 | |||
28th wk | 0.7 ± 0.1 | 1.1 ± 1.8 | |||
Resistance index | 12th wk | 0.69 ± 0.15 | 0.66 ± 0.12 |
| |
20th wk | 0.52 ± 0.06 | 0.57 ± 0.11 | |||
28th wk | 0.47 ± 0.07 | 0.59 ± 0.24 | |||
Diastolic notch | 12th wk | 10 (32.3%) | 8 (21.1%) |
| |
20th wk | 1 (3.0%) | 6 (15.8%) |
| ||
28th wk | 1 (3.6%) | 3 (8.6%) |
|
Remarks: right uterine artery RI was significantly improved in the yoga group, while the PI was near significance along with the RI and PI of left uterine artery.
The S/D ratio, the PI, and the RI parameters of the umbilical and fetal middle cerebral arteries were assessed at the 20th and 28th weeks of gestation through ultrasound Doppler velocimetry. It was not possible to measure these parameters at the 12th week of gestation. All the parameters, except for the RI of the umbilical artery, which showed near significant results, were significantly improved in the yoga group at the 28th week of gestation. All the parameters for the umbilical artery were significantly better in the yoga group even at the 20th week of gestation. The results for the fetoplacental circulation are listed in Table
Fetoplacental circulation between groups.
Gestational age | Mean ± SD |
|
|||
---|---|---|---|---|---|
Yoga ( |
Control ( | ||||
Umbilical artery | Systolic/diastolic ratio | 20th wk | 2.7 ± 0.41 | 3.3 ± 1.1 |
|
28th wk | 2.6 ± 0.5 | 2.9 ± 0.6 |
| ||
Pulsatility index | 20th wk | 1.01 ± 0.18 | 1.37 ± 0.34 |
| |
28th wk | 0.87 ± 0.18 | 1.05 ± 0.23 |
| ||
Resistance index | 20th wk | 0.65 ± 0.05 | 0.70 ± 0.09 |
| |
28th wk | 0.63 ± 0.08 | 0.66 ± 0.06 |
| ||
|
|||||
Fetal middle cerebral artery | Systolic/diastolic ratio | 20th wk | 5.02 ± 1.47 | 5.77 ± 2.04 |
|
28th wk | 5.05 ± 1.64 | 6.62 ± 2.26 |
| ||
Pulsatility index | 20th wk | 1.86 ± 0.45 | 2.18 ± 0.67 |
| |
28th wk | 1.74 ± 0.53 | 2.28 ± 1.10 |
| ||
Resistance index | 20th wk | 0.77 ± 0.07 | 0.80 ± 0.07 |
| |
28th wk | 0.80 ± 0.08 | 0.85 ± 0.08 |
|
bCalculated using Mann-Whitney test.
Remarks:
The arterial resistance index (RI) has been defined to be a measure of pulsatile blood flow that reflects the resistance to blood flow caused by microvascular bed distal to the site of measurement [
This randomized control study on yoga-based visualization and relaxation in high-risk pregnancy has shown significantly better uteroplacental and fetoplacental blood flow velocity in the yoga group compared to the control group. The RI in the right uterine artery was significantly better in the yoga group (
Interestingly, the umbilical RI was highly significant at the 20th week of measurement (
Use of complementary and alternative (CAM) therapies during pregnancy has been on the rise globally [
Antiplatelet agents, primarily low-dose aspirin [
The sample size for this study is too small to draw any definite conclusion on the mechanism of action of yoga on the reproductive blood flow during pregnancy. Nonetheless, we can examine potential previously argued hypothesis for the results that were observed in this study. Pregnancy itself is a stressful period in a woman’s life and it is now believed that it exerts a larger load on the cardiovascular system than previously assumed [
Finally, the yoga intervention used in this study was designed with emphasis on the yogic visualization and guided imagery, which, as previously stated, intended to test the hypothesis that when attention is moved to an area of the body, it causes prana to move in that area, which in turn improves circulation in the surrounding tissues. These are not exactly new ideas. Tirumular, an 8th century South Indian saint, once said, “Where the mind goes, the prana follows” [
In our earlier publication, we have shown that the yoga group had lesser number of complications than the control group which could be related to this improved blood flow. Significantly fewer occurrences of pregnancy induced hypertension (
Three participants in the yoga group experienced PIH and none suffered from preeclampsia or eclampsia. In the control group, there were 11 subjects with PIH, 4 with preeclampsia, and 2 with eclampsia [
The sample size was too small to draw any conclusion on the potential effects of yoga on the diastolic notch of uterine arteries. The high-risk nature of the population for this study contributed to the lower sample size by increase of dropouts due to pregnancy complications. Another reason could have been our strict inclusion criteria that made recruitment more difficult. Furthermore, some of the subjects delivered in their hometowns and we were not able to collect all the necessary data required by the study from the corresponding institutions. This resulted in missing data. In addition, the other hospitals may have used different protocols in delivery, performing C-section or administrating medications during the delivery that could have impacted the outcome data but not the Doppler data that is the focus of this paper. Finally, one of the objectives of this pilot study was to gain knowledge for the design of a larger and more comprehensive follow-up study. We plan to include collection of other parameters, such as gravidity and parity, in the future studies.
A great deal of efforts was spent in adhering to high standards of randomization and blinding. The data was very carefully entered, double-checked, and analyzed. Also, the sample profile matched closely that of the Bengaluru metropolitan population.
We recommend a follow-up multicenter RCT with larger sample size powered by the data from this study. We also suggest three groups for such a trial, one control group (walking) and two study groups. One of the study groups will do only the visualizations and guided imagery while the other study group practices the rest of the interventions alone.
The result of this randomized controlled trial of yoga in high-risk pregnancy has shown that yogic visualization and guided imagery can significantly reduce the impedance in the uteroplacental and fetoplacental circulation. This pilot data can be used to power larger studies to confirm these results and elaborate on the mechanism of action.
Raghuram Nagarathna, Rita Mhaskar, Arun Mhaskar, Annamma Thomas, and Sulochana Gunasheela are coauthors.
The authors declare that there is no conflict of interests regarding the publication of this paper.
This study was funded by a grant from the Central Council for Research in Yoga & Naturopathy (CCRYN) of Department of AYUSH within the Ministry of Health of the Government of India (Grant no. 13-1/2010-11/CCRYN/AR-90).