Patients with a diagnosis of HRP, who were on regular follow-up and willing to give consent for the study, were recruited from the outpatient services of the Medical College and Hospital in Bangalore, South India. A total of 68 patients were included in the study with their age ranging from 19 to 31 [mean (SD), 27.4 (5.1)] years. The reasons for exclusion of 42 women from the study were as follows: moved away (n = 20), drop out (n = 5) and irregular attendance (n = 17). There were 18 (8 yoga, 10 control) women with bad obstetric history, 14 (6 yoga, 8 control) with age factor, 14 (6 yoga, 8 control) with genetics, 13 (6 yoga, 7 control) with obesity, 8 (4 yoga, 4 control) with multiple pregnancy, and 1 (control) with diabetes. Signed informed consent was obtained from all subjects before randomization and the project had received clearance from the ethical committee of University in Bangalore, South India prior to recruitment of the subjects. Furthermore, the project was approved by the Institutional Ethical Review Board and the registration number was IERB/1/861/08. The project was also registered with Clinical Trial Registration of India (CTRI) with registration number as CTRI/2011/10/002096. Patients with a diagnosis of HRP were selected using following criteria:
Pregnant women with (1) hypertension at the time of recruitment/prior to this pregnancy, (2) diabetes at the time of recruitment/prior to this pregnancy, (3) past history of pregnancy complications such as pregnancy-induced hypertension (PIH), gestational diabetes mellitus (GDM), pre-eclampsia (PE) or eclampsia (E), intrauterine growth restriction (IUGR), placental abruption (PA), and fetal death (FD), (4) multiple pregnancies, (5) extremes of age, i.e., <20 or > 35 years, (6) BMI > 30, (7) family history (sister, mother, and/or grandmother) of pregnancy complications (PIH, GDM, PE or E, IUGR, PA, FD).
Pregnant women with (1) major medical (cardiac, renal or neurological diseases) or mental illnesses (psychosis, neurosis, addictions, etc.) or with any structural abnormality of reproductive system and (2) normal pregnancy.
The present study was a single-blind randomized controlled clinical trial. Using computer-generated random numbers, 68 patients were allocated to two treatment groups: Yoga (n = 30), control (n = 38) at their 12th week of pregnancy (end of the first trimester). The power analysis (alpha = 0.01, power = 0.8, effect size = 0.81) had yielded 27 subjects per group.
The YT module used in this study was selected carefully by the investigators based on previous studies.[13
] This module was a holistic approach to well-being at physical, mental, emotional, intellectual, and spiritual levels and was designed to reduce chronic psychological stress experienced during HRP. The practices for the control group involved standard simple prenatal stretching exercises approved by the Society of Obstetricians and Gynecologists of Canada (SOGC) Clinical Practice Obstetrics Committee, the Executive and Council of SOGC, and the Board of Directors of the Canadian Society for Exercise Physiology.[16
The outcome measure was the perceived stress scale (PSS) scores. The PSS is a widely used valid psychological instrument for measuring perception of stress in the Indian population with a Cronbach's α for reliability of 0.84.[17
] This questionnaire consists of 10 questions about experiencing stress during the previous month and coping with the stress, and has a 5-point scoring system from 0 to 4 with reverse scoring for 4 positive items (the 4th
, and 8th
] The final score is a sum of the scores for all 10 items. The PSS questionnaire was administered at the baseline, i.e., 12th
week of pregnancy, 20th
week of pregnancy (1st
follow-up), and 28th
week of pregnancy (2nd
Randomization was carried out using a computer-generated random number table and all baseline data were collected prior to the starting of prenatal treatment (YT module). The fact that there was no baseline differences in the yoga and control groups helped to compare the data at follow-up without adjusting for the means at baseline. This study was a single-blind, randomized controlled clinical trial where only the patients, the medical staff, and the yoga instructor knew the treatment group. The people involved in the assessments were blind to the group treatment status.
Statistical software SPSS version 16.0 (Chicago IL.USA) was used for all data analysis. When the data were found to be normally distributed by a Kolmogorov–Smirnov test (P > 0.05), the RMANOVA were used to assess the PSS scores between the yoga and control groups.