The present study was quasi-experimental and examined 93 pregnant women aged 16 to 20 weeks of gestation. Sampling was done on pregnant women participating in the childbirth preparation classes in Isfahan (Falavarjan County). Among the three centers of childbirth preparation classes, we accidentally considered a center as an intervention and another center as the control group. Inclusion criteria: willingness to participate, permission to participate in the childbirth preparation classes by a gynecologist, no disability and physical diseases, bone and joint problems, and no underlying diseases such as diabetes, hypertension, respiratory diseases, and no history of first abortion and pregnancy. Exclusion criteria: unwillingness to continue studying, migration or transfer from the county, not using the application during the intervention, obstruction of physical activity in terms of midwifery (cervical cerclage, placenta previa, rupture of membrane, preeclampsia, bleeding in the second and third trimesters of pregnancy, etc.)
After approving the proposal in the faculty and adopting the code of ethics, the researcher visited the center, and sampling was performed after explaining the research purpose to the head of the center according to the previous coordination with the researcher who attended the first session of childbirth preparation classes, and the pregnant women received training in both intervention and control groups in terms of the research purpose and the way of responding to the questionnaire. At the beginning of the study, we included 110 individuals in the study according to the inclusion criteria. Among whom 58 were put in the intervention group and 52 in the control group and 9 ones in the intervention group and 8 in the control group were excluded from the study due to migration, cancellation of the study, earlier delivery, and the lack of use of the application during pregnancy (in the intervention group), and finally the study continued with 49 individuals in the intervention group and 44 ones in the control group. All individuals in both groups completed the informed consent form. We did not mention the individuals' names in the questionnaire and the whole information was kept confidential.
In the study, we used the questionnaire to collect data before the intervention and three months after the intervention in both groups including the first part for the demographic information including: age, education level, and job.
The second part included the following constructs, including the perceived benefits (13 questions), perceived barriers (14 questions), perceived enjoyment (6 questions), perceived social support (14 questions) that were measured on a Likert scale (very agree with a score of 5, agree: 4, no idea: 3, disagree: 2, and strongly disagree: 1). Solhi et al. used the questionnaire and confirmed its validity and reliability (23).
We used the standard Pregnancy Physical Activity Questionnaire (PPAQ) to assess physical activity and Chasan Taber et al. approved its validity (24), and Abbasi et al. also evaluated and confirmed the validity of its Persian version and its reliability with a Cronbach's alpha of 0.81 (25), and Ahmadi et al. evaluated and approved its validity using the opinions of some faculty members at Isfahan University of Medical Sciences, and evaluated and confirmed its reliability with a Cronbach's alpha of 0.8 (26). In the present study, the reliability of the questionnaire was above 0.8. The questionnaire measured the levels of physical activity by questions about four different fields: 1- household/caregiving (13 questions) among which we eliminated three questions about lawn mowing, care, and playing with pets for localization; 2- transportation (3 questions); 3- occupational activity (5 questions); and 4- sports/exercise activity (8 questions) and we evaluated a total of 29 questions. Respondents were asked to report the duration of participation in each activity and select a category for each activity that best approximated the amount of time spent in the activity during a day of the current quarter of the year. We calculated the activity intensity based on MET as a unit for estimating metabolic expenditure in physical activity (a MET is equivalent to 3.5 ml of oxygen per kilogram of body weight). To calculate the intensity of activity, we multiplied the amount of MET of each activity by the time spent in a day. An activity with a MET of less than 1.5 refers to sedentary activity, MET of 1.5- 3 is light activity, MET of 3–6 is moderate activity, and MET of higher than 6 is intense activity (24).
For designing the educational content, we first performed the need assessment on three groups of pregnant mothers, teachers of childbirth preparation classes, health education specialists, and experienced midwives, and then prepared the appropriate educational content covering their needs under the supervision of health education specialists, a senior midwife, and a sports medicine specialist in text, photos, videos, and gifs from the ministry's reputable sources such as Pregnancy and Childbirth Preparation Books and other reliable sources, and then the content was reviewed by the research team. After confirming the content, an IT expert and we performed software programming and application development. In the content, we sought to focus on the perceived benefits and barriers, social support, and perceived enjoyment.
The content of the application contained 12 main domains: 1. Description of physical activity, 2. Physical and mental benefits of exercise in the pregnancy, 3. Different types of proper pregnancy exercise (walking, swimming, tennis, yoga, cycling, mountaineering, and water sports) (for the intervention of perceived benefits), 4. The way of doing daily activities (ways of correct stance, lifting objects, sleeping, and sitting properly, doing properly the rest of house affairs like ironing, sweeping, and driving; and all of the educational principles were with a photo display), 5. Planning for exercise, 6. Time to stop exercising and cases of the absolute prohibition of exercise (to intervene on the perceived barriers), 7. Massage (including massage of the head, back, abdomen, shoulders, perineum with photo display) (explaining the massage that could be done by spouse, colleague, parents, to intervention on the perceived social support), 8. Stretching exercises (exercises in cross-legged sitting, in lying-down position, pelvic floor and groin exercises along with photo display), 9. Relaxation, 10. Reminding important points while doing exercises, 11- Exercise demonstration movements (showing a few short sports movements), and 12. Educational videos (eight videos including videos of standing exercise movements, Stretching exercises, exercises for preventing constipation and strengthening the pelvis, and doing simple exercises for better delivery), and as a whole, playing music, proper training along with sports photos and gifs, colorful background and marginal content, and making the content attractive to intervene on the perceived enjoyment construct.
After creating the application and final checking, the app was given to the intervention group for use, and the account in the app was given to specialists to contact the pregnant mothers. In the intervention group, the necessary training was provided by the researcher about the way of using the application and everyone was encouraged to use the application during the week through the national messenger on cyberspace. It should be noted that the information was completed by the above-mentioned questionnaire before and three months after the intervention in both groups and the data were analyzed using SPSS20. The descriptive statistics (frequency, percentage, mean, and standard deviation) and the Chi-square test was used for the qualitative variables. We also used the statistical analysis including t-test to compare the mean scores of physical activity and constructs before the intervention and three months after the intervention between the intervention and control groups, and compared the mean scores of physical activity and constructs before and after the intervention in both groups using the Paired t-test. The significance level was considered to be less than 0.05.