Study Design
This study was made using concurrent triangulation mixed method design conducted from December 2015 through June 2016. Pregnant women who came to pregnancy policlinic for routine antenatal care and reported stress perception scores were five and above according to Visual analogue scale (VAS) eligible to enroll.
The study was approved by the institutional ethics committee of Ege University Medical Faculty (Decree No. 15-10/3) in accordance with the Declaration of Helsinki Research Principles. All participating women provided informed consent before enrolling in the study. The women's names were not used due to ethical concerns, and they were coded as P1, P2 and so on.
Study Subjects and Setting
All women at the beginning of their second trimester were informed by researchers at the hospital clinic of the possibility of taking part in the study if they had a stress perception. The inclusion criteria were as follows: 1) women who came to pregnancy policlinic for examination 2) who were literate 3) in the age group between 19 and 35 years 4) on 12th–18th gestational week 5) stress perception scores were five and above based on Visual analogue scale (VAS), 6) no other pregnancy contraindication 7) no history of abortion or curettage 8) resident in the city of Izmir, Turkey. Through Informed Consent Form, written consent of the participants was received, and to determine their sociodemographic characteristics, Pregnant Women Description Form was applied. Following the application of research forms, the women were categorised randomly to the prenatal yoga programme group or control groups using a random number table. The women in the prenatal yoga programme group were informed about the starting date of yoga and the location of the training centre. The interviews were made in the training centre through Semi-Structured Interview Form (SSIF).
Using the Statistical and Power Analysis Size Software 2005 (NCSS-PASS) program, the power of research was calculated. The mean difference of VAS in the intervention group between the first and third measurements was found −7.12±1.97. The mean difference of VAS as for the control group between the first and third measurements was found 1.35±1.11 (α = 0.05). The power of research was calculated to be 100%, and the quantitative data collection process was finalised (n=31). Within the qualitative process, semi-structured interviews were made using the SSIF created following the direction of Selye's GAS theory and recorded by audio recording device. The voices of 21 women who gave their consent for sound recording before prenatal yoga programme and 15 women after prenatal yoga programme were digitally recorded and were transcribed verbatim.
Assessment Tools
A 3-part survey was used for data collection. The questionnaires included a pregnant woman description form, a visual analog scale for measuring stress score, and the Semi-Structured Interview Form.
Pregnant Woman Description Form (PWDF)
This form, an investigator developed survey, consisted of 26 questions in total to determine the sociodemographic and obstetric characteristics of pregnant women.
Visual Analog Scale (VAS)
This was preferred because it is a fast and simple scale for evaluating perceived stress. This helps the individual to define stress and express himself or herself without using long scales. The VAS rating system consists of a 100- mm line that represents pain along a continuum of 2 extremes, from no pain (a score of 0) to extreme pain (a score of 10). In addition, this eliminates the defects that may arise out of use of long scales in the cases in which communication is challenging due to the differences between the interviewer and the interviewee's educational background. It was determined that VAS was significantly effective as much as the other scales used for measuring stress perception [20].
Semi-Structured Interview Form (SSIF)
This form is based on Hans Selye's GAS Theory. With the aim of determining its functionality and the period of interview, pilot-interviews were made with five women using its first version created to ensure the validity and reliability of the form. The form was reviewed and put into final form following these interviews. In the first interview made before the yoga intervention to the accompaniment of Semi-Structured Interview From, the longest sound recording took 22 minutes four seconds while the shortest sound recording took five minutes 27 seconds.
Data Collection
The quantitative and qualitative data were collected synchronously within the data collection process of the research as a requirement of the research pattern. The aim of this pattern is to explain a research problem by adding the qualitative data to research process by means of conducting an intervention program [21].
Through Informed Consent Form, written consent of the participants was received, and to determine their sociodemographic characteristics, Pregnant Women Description Form was applied. Following the application of research forms, the women were categorised randomly to the prenatal yoga programme group or control group.
The Prenatal Yoga Programme Group
The stress levels of pregnant women in the yoga intervention group (n=31) were measured with VAS at the first study visit. and the pregnant women who were scored five and above and who fulfilled the research criteria, were included into group. The pregnant women were directed to pregnancy training center of relevant hospital for yoga program which was initiated within the same week. The pregnant woman who came at the data and time notified to her, was interviewed to the accompaniment of Semi-Structured Interview From and first qualitative data set was collected and then, yoga practice was started. The pregnant women in the intervention group did yoga in the pregnancy training center for 60 minutes twice weekly throughout four weeks. In the second week of yoga intervention, the stress perceptions of pregnant women were measured with VAS. Immediately after the completion of four weeks yoga program, the stress perceptions of pregnant women in yoga intervention group (n=31) were measured with VAS and the interviews were made with the pregnant women who accepted to make interview (n=15) within the direction of Semi-Structured Interview Form and their experiences devoted to the effect of yoga on stress perception were determined. In the second interview consisting of four questions, the longest sound recording took five minutes 39 seconds while the shortest sound recording took two minutes one second.
Control Group
The stress perceptions of pregnant women in the control group (n=31) were measured by applying VAS at the first study visit, two week later and at the end of fourth week synchronously with the yoga intervention group.
Intervention procedure
At the beginning of yoga practice, the researcher requested the pregnant women to take a relaxed sitting position (block, mat or ball in the following gestational weeks), put their hands at on their legs in the way they would feel comfortable, close their eyes and focus on their bodies without holding on mental flow. With the verbal soothing directives given during the concentration phase which took approximately 3-5 minutes, it was aimed to focus the pregnant women to their bodies mentally and to increase the physical awareness. Only a breath awareness exercise was made following the concentration. The researcher constituted the standing pose part of yoga intervention from the standing poses that the pregnant women will do in the second and third trimester and it was practiced for approximately 30-40 minutes based on the flow of course. The standing poses applied in the research were practiced by doing physically and giving verbal directives by researcher in a controlled way and they were adapted according to feedbacks of pregnant women. The yoga exercise at which concentration, breathing and standing poses were applied respectively, was finally completed with a deep relaxation which took at least five minutes. During the deep relaxation, the attention was gathered on the body parts where the tension was felt, to relax each part of body respectively. The pose of lying the body forward on the ball or left-side lying supported with mat, was used as deep relaxation pose. Each yoga intervention took approximately 60 minutes.
Data processing and Analysis
The primary aim of this study was to compare 4-week changes in stress scores measured by the VAS in each group and between the 2 groups. A secondary aim was to determine the experiences of pregnant women have been revealed through interviews in a realistic and integrative way in prenatal yoga group.
In the quantitative data analyses, the Statistical Package for the Social Sciences (SPSS) 16.0 was used, whereas NCSS-PASS programmes were used to determine the power of research. On the other hand, Fisher's exact chi-square test, Wilcoxon-signed item value, Friedman's variance analysis and Mann–Whitney's U test were conducted in the comparative analyses [22]. The level of significance in all analyses was set at P less than .05.
Qualitative coding and analysis of themes followed a general inductive approach. NVIVO 11.0 plus statistical programme was used for coding, revealing the themes, numerical analyses of qualitative data and visualising the findings [22]. The SSIF of each pregnant woman was transferred to NVIVO 11.0 individually. Three specialists in the qualitative research read the transcripts iteratively and prepared a list of codes independently, and then they compared these lists, edited the codes and reached a consensus on the definitions of the codes. Specialists familiarised themselves with the raw data then discussed the conceptual framework of themes. Thematic analysis was conducted in context of stress perceptions, barriers and benefits of yoga participation.Themes were grouped for reporting and each theme was illustrated by direct quotations from participants.