Following a descriptive-analytical design, the current study aimed to analyze the determinants of EBF intention using the IBM framework on 292 eligible pregnant women referred to the health centers in the city of Birjand. The sample size was estimated using the Mean estimation formula and following the study by Rahimi et al. (
14). Participants were selected using the using multistage cluster random sampling technique. To this end, the city of Birjand was divided into four similar regions, and a health center was selected in each region using the simple random sampling technique from the list of health centers located in each region. Afterward, in each center, the list of potentially eligible pregnant women was retrieved from the SIB website. Due to the sample size and population size, the samples of each center were selected using systematic random sampling. The inclusion criteria were informed consent to participate in the study, having at least primary literacy, not having a job history in works related to the health sector, not being a healthcare worker, and being healthy (both physical and mental health). Data were collected using a researcher-made questionnaire with two sections on demographic information (age of mother, education level, spouse job, etc.) and items related to the IBM. The "awareness" dimension contained 7 items, and each correct answer choice had one point, and each incorrect answer had zero point; the "experiential attitude" contained 5 items; instrumental attitude included 8 items; descriptive norm included 4 items; injunctive norm included 8 items; perceived behavioral control included 6 items; behavioral intention contained 3 items; and perceived self-efficacy included 8 items. The responses were scored based on a 5-point Likert scale, ranging from 1 ("strongly disagree") to 5 ("strongly agree"). A deductive approach was followed in order to develop items, which requires a theoretical definition of the construct under examination. In this study, Ajzen’s theoretical framework was used as the theoretical foundation to define the structure of items. The item development process began with a comprehensive review of published research on IBM and its measurement. Also, two focus groups were conducted to gain a comprehensive understanding of the IBM constructs in the context of Iranian pregnant women and to propose items related to the IBM constructs. A series of focus groups were held with experts on health education and health promotion. The validity of the questionnaire was evaluated by 10 experts in the field of Health Education and Health Promotion. For this reason, generated items were subjected to a content validity assessment [content validity ratio (CVR) and content validity index (CVI)]. In order to evaluate the CVR, participating experts were asked to rate each item of the questionnaire on a 3 point Likert scale (i.e. necessary, helpful but not necessary, and not necessary). The obtained ratios for each item were compared with the numbers provided by Lawsche (
15). If the calculated value was greater than the number given in the Lawsche table (for this study: CVR > 0.62), the item was considered necessary. Lynn's descriptive method (item-CVI) was employed to evaluate the CVI (
16). Based on the pattern of Lynn, the experts were asked to rate each item concerning its simplicity [ranging from 1 ("not simple") to 4 ("strongly simple")], relevance [ranging from 1 ("not relevant") to 4 ("highly relevant")], and clarity [1 ("not clear") to 4 ("strongly clear")] on a four-point Likert scale. Based on the Lynn method, if the number of experts is 6 or more, the index should not be less than 0.78 (
16). A pilot study was conducted on 20 eligible women to evaluate the reliability of the questionnaire. Also, the internal consistency of items was evaluated using Cronbach's alpha. A coefficient of 0.85 was obtained for the questionnaire. Concerning its dimension, a coefficient of 0.91 was obtained for the perceived self-efficacy, 0.69 for experiential attitude, 0.7 for the instrumental attitude, 0.87 for descriptive norm, 0.98 injunctive norms, and 0.91 for the perceived behavioral control. The questionnaire was filled out in a self-administered manner. However, those unable to fill the questionnaire were interviewed verbally, and their responses were noted.
Initially, the objectives of the study were described for eligible participants. Then, if agreeing, written informed consent was obtained. Also, they were ensured about the confidentiality of their information. In addition, they were informed that they can withdraw from the study at any time. The study is approved by the Ethics Committee of the Birjand University of Medical Sciences (Ir.BUMS.REC.2020. 493). Data were analyzed using SPSS version 19 by descriptive statistics, Pearson correlation test, and regression analysis. Statistical significance was considered when P-value < 0.05.