Trial design
This study was designed as a clinical trial and was registered at the Iranian Registry of Clinical Trials on 27/12/2018 (IRCT20181214041963N1). The report of this clinical trial is based on the CONSORT 2010 checklist [17].
Participants and setting
This study is a Main part of the findings of a larger study examining the effects of labor pain and anxiety. This randomized clinical trial with three parallel groups was performed on 93 mothers in Allameh Bohlool Gonabad and Sajadieh Torbate Jam Hospital in Iran (protocol of labor in two center was similar). Sampling was done from February 2018 to June 2019. Inclusion criteria included: consent to participate in the study, gravida 1or 2, singleton pregnancy with live embryo, entry into active phase of childbirth, maternal age between 18 and 35 years, pregnancy stage 37–41 weeks, lack of medical and mental illness, lack of abnormal embryos, cephalic manifestations, low risk pregnancy, healthy caul or less than 8 h have passed since their rupture, no history of motion sickness, no blindness, no addiction, and estimated weight of the fetus up to 4000 g. Exclusion criteria were: mother’s unwillingness to cooperate, midwifery problems, use of Entonox and spinal and epidural anesthesia, chewing gum less than 20 min and watching virtual reality film less than 20 min.
Sample size and randomization
Sample size was calculated using G-Power software based on numerical methods to obtain n number of samples in k group (k = 3). An effect size of f was equal to 0.35% of the first type error of maximum 5%, test power 80% and number of comparison groups was set at three, which required a sample size of 84. The final sample size was 93 mothers in three groups with 10% fall.
$$\frac{\sum \left(\overline{{\boldsymbol{y}}_{\boldsymbol{L}}}-\overline{{\boldsymbol{y}}_{..}}\right)/\left(\boldsymbol{k}-\mathbf{1}\right)}{\sum \sum \left({\boldsymbol{y}}_{\boldsymbol{ij}}-\overline{{\boldsymbol{y}}_{\boldsymbol{L}}}\right)/\left(\boldsymbol{n}-\boldsymbol{k}\right)}-{\boldsymbol{F}}_{\mathbf{1}-\boldsymbol{\alpha}}\left(\boldsymbol{k}-\mathbf{1},\boldsymbol{n}-\boldsymbol{k}\right)>{\boldsymbol{F}}_{\mathbf{1}-\boldsymbol{\beta}}\left(\boldsymbol{k}-\mathbf{1},\boldsymbol{n}-\boldsymbol{k}\right)$$
Sampling was done Convenience Sampling method and 6 blocks were used for random allocation of samples to each group. 6 possible modes are listed for the blocks and assigned to each block a number from 1 to 6 and randomly selected a number between 1 and 6, followed by individuals based on the block corresponding to the number selected to the virtual reality group (B), chewing gum group (C) and control (A) were assigned. Mothers and researchers were not blind to the intervention, while the statistical analyst who performed the data analysis was one-blind.
Study instruments
Data collection tools included demographic and fertility characteristics questionnaires, visual analogue of pain and Spielberger’s anxiety questionnaire. The demographic questionnaire was provided to ten faculty members for review and corrective comments were applied after the survey. The visual analogue of pain is a 10-mm line that the beginning and end of it are denoted by the numbers 0 and 10. So that zero means pain and number 10 is the most severe pain that one feels in the lower abdomen and back. The Visual Anxiety Scale is a standard tool and its validity and reliability have been globally proven (r = 0.88) [18]. The Spielberger’s Anxiety Inventory is a standard questionnaire that consists of 20 items of explicit anxiety section. In the range of 4 Likert options, scores range from 1 to 4 (not at all, sometimes, generally, very much) and on a general scale, 20 to 80 are measured. A score of 20 indicates the lowest level of anxiety and a score of 80 indicates the highest level of anxiety. Each of the test terms is assigned a score of 1 to 4 based on the answer. A score of 4 indicates a high level of anxiety. Scoring is inverted for expressions that indicate anxiety. Depending on the item, the response scores will be assigned to 4–3–2-1 instead of 1–2–3-4. Phrases that indicate the absence of anxiety are reversed when scoring [19]. The validity of this questionnaire in Iran has been confirmed by Behrouz Mahram (1993). The reliability of the questionnaire was calculated by Cronbach anxiety ‘s alpha method of 0.889 [20].
Interventions and outcomes
At the beginning of the study, after obtaining informed consent from the research units, a demographic and fertility questionnaire was completed by questioning Mother and her hospitalization file. Before the intervention, the researcher trained the use of pain visual analogue for three groups. Pain visual analogue and Spielberger Anxiety Questionnaire were completed by all research units before intervention. The chewing gum group was given a 1 g mint gum without sugar (with official permission from the Ministry of Health of Iran) in two stages, first at the beginning of the active phase (4 to 5 cm dilatation) and the second time at 7–8 cm dilatation to chew at their normal speed for at least 20 min. In the virtual reality group, virtual reality glasses containing 360-degree video with nature landscapes (Samsung Gear VR Virtual Reality Headset with Samsung Mobile S7) were performed twice, the first intervention was performed at the beginning of the active phase (4–5 cm dilatation) and the second intervention at 7–8 cm dilatation. Each intervention lasted for 20 min. The intervention groups (virtual reality and chewing gum) completed the pain visual analogue and the Spielberger Anxiety Inventory immediately after each intervention as well as the first 30 min after each intervention. In the control group, only routine maternity unit care was received according to the national protocol of midwifery care similar to the intervention groups. Routine delivery unit care Such as receive analgesia) oxytocin in the first and second stages of labor, misoprostol, pethidine, hyoscine, promethazine and atropine (except for the use of Entonox and spinal and epidural anesthesia, control fetal heart rate, vaginal exams, vital signs recording and more etc. Like the other two groups, pain visual analogue and anxiety questionnaire were measured simultaneously with the intervention group. All interventions in the two hospitals, including the implementation of virtual reality, chewing gum and recording the relevant questionnaires were performed by a postgraduate midwife who had received the necessary training in the morning, noon and night shifts.
Statistical analysis
Data were analyzed by SPSS version 22 software. Data were analyzed using ANOVA and Kruskal-Wallis statistical tests and Chi-square test for qualitative data. Tukey was used to compare the two groups. Statistical analyst did not know the type of groups. Significance level was considered 0.05 in this study. Ethical considerations in this study include obtaining informed consent from research units by providing complete information about the intervention and control group, permitting exit from research at any stage, ensuring the confidentiality of the research data, fully observation of ethics, and trusting other research, and publishing accurate and real results.