The present study aimed to investigate the effect of educational intervention based on the TPB on promoting nutritional behaviors preventing anemia in a sample of Iranian pregnant women. There are several risks to mothers during pregnancy. Anemia is one of the most common blood disorders and risks during pregnancy that may affect the health of mother and fetus; therefore, identifying the factors affecting the improvement of nutritional behaviors preventing anemia in pregnant women is of great importance.
In the present study, the mean score of knowledge, attitude, subjective norms, perceived behavioral control, behavioral intention and nutritional performance in both experimental and control groups before the intervention were not statistically significant. This is consistent with the results of some other studies [8, 17, 19, 20]. Perhaps the low mean score of these constructs before the educational intervention is due to the lack of codified and model-oriented training programs using participatory programs and combined educational methods [21].
However, three months after the intervention program, the mean score of knowledge, attitude, subjective norms, perceived behavioral control, behavioral intention and nutritional performance in the experimental group were statistically significant with that of the control group. This was consistent with the results of other studies, indicating the effectiveness of TPB-based educational intervention [8, 22]. Studies by Kamalifard, M. et al. [21], Anderson, A. S. et al. [23] concluded that the training package in their study could improve the nutritional knowledge, attitudes and behaviors of pregnant mothers.
The mean score of knowledge in the present study in the experimental group increased significantly after the intervention. This, consistent with other studies, showed that to improve nutritional behaviors during pregnancy, increasing mothers’ knowledge is a necessary and effective [24, 25]. Of course, the willingness of the participants to participate in the training programs is very important; for example, the results of a study by Jarrah S. S. et al. showed that most participants are very aware of the prevention of anemia and iron deficiency, but many of them wanted to know more [26].
A study by Pawlak R. et al. showed that applying this theory could lead to a positive attitude towards behavioral intention and improve nutritional behaviors [27]. In this regard, it can be concluded that in the present study, educational intervention based on the TPB could be effective in improving the attitude of pregnant mothers. Consistent with our study, the results of other studies indicated that educational programs have an effective role in creating a positive attitude toward nutritional behaviors [8, 28].
Subjective norms are considered as a secondary predictor of behavioral intention, and a person who believes that certain people approve of behavior and are motivated to meet their expectations has positive subjective norms. In this study, spouses and officials of health centers were considered as subjective norms. Similar studies have also considered the role of spouses and friends in subjective norms [8, 29]. Based on Table 4, the mean score of subjective norms in the experimental group was significantly different after the educational intervention, which is consistent with the results of some other studies [17, 19]. However, this is not consistent with the results of studies by Ahmadi et al. [30] and Pawlak et al. [27]. This could have a variety of reasons, including cultural differences and even people who are considered important in the study. For example, in their study, Jarrah SS et al. Discuss the role of cultural conditions in transmitting important health information to others.
Perceived behavioral control refers to an individuals’ understanding of how much control they have over their voluntary actions. Our intervention program in the present study could improve the perceived behavioral control in the experimental group. The results of this study were consistent with the results of the study by Alami et al. [17]. Of course, several studies have examined this issue from different aspects. Lack of financial resources, inadequate access to health care centers are among the concerns associated with reducing healthy nutritional behaviors [26, 31]. Or, for example, another study states that if pregnant women feel that environmental factors such as facilities and barriers are under their control, they will have desirable nutritional behaviors [27].
Based on the TPB, the most important determinant of behavior is behavioral intention. In this study, behavioral intention also showed a significant increase in the experimental group three months after the educational intervention. This is consistent with the results of other similar studies [8, 17, 19].
The mean score of nutritional performance in the experimental group showed a significant increase after the educational intervention, while no significant change was observed in the control group. The results of this study showed that the training program was effective in promoting optimal nutritional behaviors and was consistent with the results of other similar studies [19, 32]. Also, Jalambadani et al. could significantly improve the nutritional behaviors associated with folic acid consumption in pregnant women after the intervention [22].
The results of this study showed that implementing intervention programs using theory and model of health education and health promotion can effectively improve the desired preventive behaviors. The results of numerous similar studies that have used the TPB support the results of the present study [8, 17, 22].
The present study also had some limitations. Household economic status was one of the variables there search team was forced to disregard this variable because of the participants’ lack of clear responses to the issue, and the lack of accurate information on their economic status in the household file.