Study design and participants
This cross-sectional descriptive-analytical study was carried out in 2018 in health centers of Tabriz, Iran, on 483 mothers with vaginal childbirth 4–16 weeks after delivery.
Women with a singleton first pregnancy and gestational age of ≥ 38 weeks, normal pregnancy and natural labor, and perfect perceived physical health who were willing to participate in the study were enrolled. The exclusion criteria included suffering from/having a history of mental illnesses, experiencing a stressful life event in the past three months, hospitalized neonate due to a postpartum illness, neonate abnormality, and refusing to complete the questionnaire.
Sample size
Based on the results of Ghanbari-Homayi et al. (2019) study and with considering the Standard Deviation (SD) = 0.73, precision (d) = 0.05 around the mean (m = 2.71), α = 0.05 and power = 90, the sample size was calculated as 226. With considering the design effect equal with 2 due to cluster sampling method, the final sample size was calculated as 452 and 483 individuals were selected as the final sample to compensate for the potential loss to follow-up [19].
Sampling
After obtaining the approval of the Ethics Committee of Tabriz University of Medical Sciences (ethical code: IR.TBZMED.REC.1397.147), one-fourth of all health centers in Tabriz were selected using the website www.random.org and through cluster random sampling. Using available health records, the list of mothers in their 4–16 postpartum weeks was prepared, and the number of samples per health center was determined randomly using proportional allocation. The researcher called the selected mothers and asked them to attend the respective health center at a specific time. The participants were fully informed about the research objectives. Then, they signed written consent forms and completed the questionnaires.
Data Collection Tool
The data were collected using the socio-demographic, the short form Questionnaire for assessing the Childbirth Experience (QACE), Mental Health Inventory (MHI), and Barkin Index of Maternal Functioning (BIMF).
A researcher-made socio-demographic questionnaire was used to obtain information about mother’s age, educational qualifications of mother and her spouse, their job, their income status, infant’s gender, pregnancy status (planned or unwanted), etc. The content and face validity of this questionnaire was confirmed.
The QACE was used to collect relevant data. The thematic areas of this 13-item tool included feelings (items 1, 2, and 3), relationship with staff (items 4, 5, 6, and 7), first moments with the infant (items 8, 9, and 10), and feelings one month after the delivery (items 11, 12, and 13). Items 8–13 measured the consequences of this experience. The responses included completely (score 1), relatively (score 2), not much (score 3), and not at all (score 4), which were scored using a 4-point Likert scale. The negatively worded items (including items 1, 12, and 13) were reversely scored; thus, higher scores indicated a more negative experience [20]. The reliability of this questionnaire was measured using test-retest design and by conducting a pilot study on 20 individuals with a two-week interval and it was confirmed by determining intra-class correlation coefficient (ICC = 0.83 (0.56 to 0.93)) and Cronbach’s alpha coefficient (0.82).
A questionnaire was used to collect the data related to maternal functioning. The thematic areas of this 20-item tool included self-care (items 2, 11, and 13), infant care (items 12 and 14); mother-child interaction (items 4, 5, and 15); psychological well-being (items 1, 2, 3, 5, 7, 10, 11, 16, 18, and 20); social support (items 6, 8, and 9); management (items 7, 11, 13, 14, 17, and 18), and adjustment (items 17 and 19). The responses included “strongly disagree”, “disagree”, “somewhat disagree”, “no idea”, “somewhat agree”, “agree”, and “strongly agree”. The mothers were asked to answer questions based on their feelings over the past two weeks. The negatively worded items (i.e. items 16 and 18) were reversely scored and a total maternal functioning score ranged from 0 to 120. Higher total scores indicated higher levels of functioning. The Cronbach’s alpha and reliability coefficients of the tool were reported as 0.88 and 0.88 [21], respectively. In the present study, the Cronbach’s alpha coefficient of the questionnaire was 0.88, and those of the relevant constructs were 0.78 (maternal competence) and 0.86 (maternal needs), which indicate an acceptable internal consistency. In the test-retest method, the intra-cluster correlation coefficient was 0.85 for the whole questionnaire, and those of maternal needs and maternal competence constructs were 0.89 and 0.88, respectively.
The Mental Health Inventory (MHI) of Veit and Ware was used to collect relevant mental health data. This tool has a short (18 items) and a long (38 items) form. The MHI is superior to other scales (such as the General Health Questionnaire), because it has been designed for normal populations, while the GHQ is a diagnostic tool used for clinical populations. The short form of MHI was used in this study, which is an 18-item screening tool used for measuring mental health in two areas of adults’ general health and psychological distress. The responses included always (score 1), often (score 2), most times (score 3), sometimes (score 4), rarely (score 5), and never (score 6). The negatively worded items (i.e. items 1, 3, 5, 7, 8, 10, 13, and 15) were reversely scored. The subdomains of “anxiety”, “depression”, “behavioral control”, and “positive affect” consisted of items “4, 6, 10, 11, 18”, “2, 9, 12, 14”, “5, 8, 16, 17”, and “1, 7, 13, 15”, respectively. Meybodi et al. [22] and Veit [23] et al. evaluated the psychometric performance of this tool. Cronbach’s alpha coefficient was calculated to measure the internal consistency of the tool. The alpha coefficient was 0.93 for the whole inventory, and those of anxiety, depression, behavioral control, and positive affect were 0.84, 0.83, 0.63, and 0.85, respectively. These findings indicated an acceptable internal consistency.
Data analysis
The collected data were analyzed in SPSS 24 software. Skewness and Kurtosis were measured to determine if the qualitative data were normally distributed. In bivariate analysis, Pearson’s correlation tests were conducted to determine the correlation between maternal functioning, mental health and their subdomains with childbirth experience. In addition, one-way ANOVA and independent t-test were performed to determine the relationship between socio-demographic characteristics with maternal functioning and mental health. In multivariate analysis, General Linear Model (GLM) was used to determine the relationship between childbirth experience with maternal functioning and mental health, while the variable of socio-demographic characteristics was considered as the control variables.