The sample size was calculated with Stata-13 software, using the data obtained from the study of Lathrop et al. (16) (m1 = 13.0, m2 = 13.75, sd1 = 1.24, sd2 = 0.81) and α = 0.05 and power = 0.80 and with 10% loss.
Inclusion criteria were age 18–35 years, no history of childbirth, live fetus with cephalic presentation, singleton pregnancy, gestational age 37 to 41 weeks, not having pregnancy complications (gestational diabetes, gestational hypertension, bleeding, placental abruption and placenta previa) or chronic medical problems (such as diabetes, high blood pressure, heart, kidney problems, etc.), dilatation of 4–5 cm at the time of hospitalization, literacy, no history of infertility, and not having a companion midwife or trained companion. The exclusion criterion was the participant's refusal to continue participating in the research.
The questionnaires used in this study included demographic and obestetric information questionnaire (including age, education, occupation, gestational age, marital satisfaction, household income, and pregnancy status), labor and delivery status questionnaire (including the duration of the first and second stages of labor, the baby's weight, the state of oxytocin intake, how the placenta came out, the person performing the delivery, and the sex of the baby), childbirth experience questionnaire (CEQ) and Rosenberg self-esteem scale.
The CEQ was designed by Dencker et al. and consisted of 22 items with 4 domains (professional support, participation, personal capacity, and safety). The modified version of this questionnaire has 23 items and the items in each area include the following: Personal capacity: items 1, 2, 4, 5, 6, 7, 21 and 22, support by professionals: items 11, 13, 14, 15 and 16, safety: items 3, 17, 18, 19, 20 and 23 and participation: items 8, 9, 10 and 12. Twenty items are scored based on a 4-point Likert scale (strongly agree, most agree, most disagree, strongly disagree) and three items are scored using the Visual Analogue Scale between 0 and 100 (0–40 = 1 ) (41–60 = 2); (61–80 = 3) and (81–100 = 4)). Negative experience items (experiencing pain, feeling tired, feeling scared, negative memories, and memories that trigger depressive thoughts) are scored inversely. The scores of the items in each domain are added and divided by the number of items in the same domain. The sum of the scores shows the score of the childbirth experience. The score range of this questionnaire is 23 to 92 and a higher score means a better childbirth experience. Psychometrics of this questionnaire has been confirmed by Ghanbari et al. in Iranian women (4).
The Rosenberg Self-Esteem Scale is a 10-item scale with 5 positive and 5 negative items. This scale measures self-esteem using 4-point Likert I strongly agree to strongly disagree. Scoring in items 1, 3, 4, 7 and 10 is strongly agree = 3 to strongly disagree = 0 and items 2, 5, 6, 8 and 9 are scored in reverse (strongly agree = 0 strongly disagree = 3). Its score range is between 0 and 30 and a score of 30 indicates the highest self-esteem. The reliability of this tool has been reported in different studies from 0.82 to 0.88 (17, 18).
In order to check the content validity of demographic and obestetric information, and labor and delivery status questionnaires, 10 faculty members of the School of Nursing and Midwifery and midwives working in health centers were asked to express their opinions on the questionnaires and their opinions were applied at the discretion of the research team. To evaluate the reliability of the CEQ questionnaire and the Rosenberg self-esteem scale, 30 women in the postpartum stage were asked to complete the questionnaires twice at intervals of ten days. Then the intra-cluster correlation coefficient (ICC) was calculated, which a value of 0.6 and above means a good agreement between the two measurements (19). In this study, ICC value of 0.78 for CEQ and 0.73 for Rosenberg self-esteem scale showed good reliability of these questionnaires.
Participants were randomly allocated to two parallel groups, in 1:1 ratio through balanced block randomization with a block size of 4. Prior to the study, the allocation sequence was determined by a person who was not present in the study. To conceal the allocation, the type of intervention was written in opaque closed envelopes and the envelopes were coded in the order of allocation. The questionnaires were also coded in order. After stating the research objectives and method for women who met the inclusion criteria, a written consent form was completed by them if they would like to participate in the study. women completed a demographic and midwifery information questionnaire before entering the study. Then, each woman received an envelope based on a predetermined sequence to be assigned to one of the intervention or control groups. In the intervention group, in addition to routine labor care, the researcher was present at the mother's bedside and was present with the mother continuously throughout the labor and up to 2 hours after delivery and provided the necessary support. This support includes emotional support (continuous presence, reassurance and praise) and information about labor progress, advice about coping techniques, comfort measures (comforting touch, massage, warm baths/showers, encouraging mobility, promoting adequate fluid intake and output) and speaking up when needed on behalf of the woman. The control group received only routine labor and postpartum care. Labor and delivery status questionnaire were completed by the midwife during study. Participants in both groups were contacted 6 weeks after delivery to complete the CEQ and Rosenberg self-esteem questionnaires. It should be noted that in this study there was no blinding (Figure. 1).
Data were analyzed using Stata-13 software. To evaluate the normality of quantitative data distribution, Shapiro–Wilk tests, histogram of data distribution as well as central tendency and dispersion were used. The results showed that all quantitative variables in this study have normal or near normal distribution. The two groups were compared in terms of demographic and obstetric variables and variables related to labor and delivery, with independent t-test or chi-square test and Fisher's exact test. One-way ANOVA/ANCOVA test was used to evaluate the differences between the two groups in terms of childbirth experience and self-esteem scores. SMD of Cohen’s d and 95% CI were calculated for analysis. Cohen’s d interpretive areas were .20–.40 considered small, .50–.70 considered moderate, .80 ≤ considered large (20). Analysis was performed by per protocol approach and the level of significance in all statistical tests was less than 0.05.