# The Effect of Educational Intervention on Improvement of Breastfeeding Self-Efficacy: A Systematic Review and Meta-Analysis

Authors: Azam Maleki; Elham Faghihzadeh; Samaneh Youseflu
Journal: Obstetrics and Gynecology International
 (2021)

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## Abstract

Background. Self-efficacy is an important psychological and motivational factor in breastfeeding, and it is a valuable framework that predicts breastfeeding outcomes and demonstrates maternal confidence in breastfeeding. The meta-analysis evaluated the effectiveness of educational interventions on improving breastfeeding self-efficacy (BSE). Methods. The English and Persian databases including Medline, Embase, Cochrane Database of Systematic Reviews (CDSR), PubMed, Web of Science, Scopus, CINAHL, Sid, IRANDOC, and Marg-Iran were systematically searched for studies published from January 2005 to December 2020. The quality of studies was evaluated using the Cochrane risk of bias tool and the heterogeneity by I2 statistic. The extracted data were analyzed using RevMan 5 statistical software and presented using random effects standardized mean difference (SMD). The funnel plot was used for evaluating publication bias. Results. Results from 40 RCTs showed that educational intervention had a positive effect on the BSE compared with the usual/standard care (pooled SMD = 1.20; 95% CI = 0.75–1.64, p value <0.001). The subgroup analysis indicated that the educational intervention was based on theory, group class format, direct method education, during the first week of postpartum, doing during pregnancy, on primiparous women, and health center setting, and the Asian region has a more effect on BSE than the others. Conclusion. Breastfeeding education is considered an influential factor in the improvement of BSE. It is recommended that breastfeeding education should be continued for several weeks after childbirth for gaining its benefit. The Asian region has a more effect on BSE than the others. Therefore, it is important to add the values in content of education in each country.


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## Body

## 1. Introduction

Breastfeeding has the health benefit and promotes physical and mental health of the mothers and their infants. So that infants who are exclusively breastfed for six months experience less morbidity than those who are partially breastfed [1]. Therefore, breastfeeding as a unique method of feeding and growth of infants in any situation and region of the world is recommended exclusively for the first 6 months of life [2]. Despite global strategy targets in low- and middle-income countries, only 37% of children younger than 6 months of age are exclusively breastfed that is below the WHO recommended rate of 50% [1]. It is even less in developed countries. Therefore, declining breastfeeding rates are universal concern [1, 2].Figure 1
PRISMA flow diagram.Self-efficacy is an important psychological and motivational factor in breastfeeding [3] and it is a valuable framework that predicts breastfeeding duration and demonstrates maternal confidence of breastfeeding [4, 5]. Consistent with Bandura’s cognitive-social theory, self-efficacy as a cognitive dynamics process evaluates people’s beliefs and their ability to perform healthy behaviors and contributes to their preventive behavior [6]. Dennis maintains that four important sources including performance accomplishment, vicarious experience, verbal persuasion, and physiologic responses can impress women’s levels of BSE [4]. Each of them may affect the mothers perceive about her breastfeeding, and it informs her BSE [4].Developing and applying effective educational programs for improving breastfeeding self-efficacy (BSE) are important concerns for health professionals, and it can help mothers initiate and maintain breastfeeding for six months after birth [7, 8]. In particular, breastfeeding educational programs have shown a positive effect on maternal breastfeeding behavior, awareness and attitude toward breastfeeding, continuity of breastfeeding, and BSE of mothers at six months after childbirth recently [5, 9, 10]. However, other studies have been reported conflicting results [11, 12]. In some studies, the effectiveness of educational programs on BSE has been reviewed. However, in these studies, the limit number of English language studies has been reviewed or the quality of the studies was not determined or type of study was included observational studies, or only one dimension of education, such as theory or telephone based, was considered [5, 13–15]. There is a wide variety in terms of the type and time of educational intervention. Therefore, reviewing the difference in setting, time, and type of educational intervention on breastfeeding self-efficacy is one of the important steps to provide practical support for developing effective educational programs and policy making. The aim of this systematic review and meta-analysis was to determine the effect of educational programs on BSE.


## 2. Materials and Methods

### 2.1. Search Strategy and Data Sources

The English and Persian electronic databases including Medline, Embase, Cochrane Database of Systematic Reviews (CDSR), PubMed, Web of Science, Scopus, CINAHL, Sid, IRANDOC, and Mag-Iran were systematically searched for studies published from 2005 to December 2020 using the following search strategies in accordance with the Mesh browser keywords and free-text words: (Feeding∗OR Breast∗OR Breastfeeding OR “Breast Milk” OR “Human Milk” OR “Breast Milk” OR Lactation OR “Milk Secretion” OR Colostrum OR “Exclusive Breastfeeding”) AND (Pregnancy OR Gestation OR “Pregnant Woman”) AND (Postpartum OR Puerperium) AND (“Self-Efficacy” OR “Self-confidence” OR “Self-concept”) AND (Education∗ OR “Health Education” OR Instruction∗OR Training) AND (“randomized controlled trial” OR “controlled clinical trial” OR randomized∗ OR randomly∗ OR trial∗ OR groups). Moreover, reference lists of the identified articles were screened. The PRISMA checklist (Figure 1) was used for reporting the search result [16]. We used a search strategy, which has been developed in Medline and adapted for other databases. We also used manual approaches, in particular, hand-searching and perusing reference lists of articles to find additional studies for systematic review. Various grey literature databases (such as Open Grey SIGLE, NTIS, Global Index Medicus (GIM), Google Scholar, World Cat, UW Libraries Search), theses, and dissertations, as well as conference proceedings, were assessed for collecting unpublished data. This study was not registered in the PROSPRO database. This meta-analysis was performed and reported in adherence with Preferred Reporting Items for Systematic Reviews and Meta-Analysis.Figure 2
The results of Cochrane risk of bias tool for the evaluation of clinical trial quality.


### 2.2. Inclusion Criteria

The studies with the following criteria were included: (1) healthy mothers with healthy baby, (2) randomized controlled trials (RCTs) with at least two groups (control and intervention) that aimed to measure mother’s BSE, (3) various forms of breastfeeding education (for example, didactic teaching session, face to face, indirect, individual, group, peer support, and workshop) combined with or without other interventions, (4) comparison groups were assigned to usual care and standard care, and (5) study published from Juan 2005 to December 2020 with restricted English and Persian. Due to the fact that the review of interventions in the last 15 years is critical for developing breastfeeding promotion strategy, the period for searching for articles in this review is limited to 2005–2020 years.


### 2.3. Exclusion Criteria

The studies with the following criteria were excluded: (1) the mothers with chronic/systemic disease, parents with preterm baby with/without admitted at NICU ward, and complication in the breast, such as mastitis, (2) a quasi-experimental study, meta-analysis, and cross-sectional and observational studies, (3) noneducational intervention such as kangaroo mother care, motivational interview, psychoeducational counseling approach, and relaxation tone, and (4) randomized controlled trials (RCTs) that measured the mothers’ knowledge or practice of breastfeeding, or breastfeeding initiation or duration.


### 2.4. Outcome

In this study, the main outcome was breastfeeding self-efficacy. The subgroup analysis was done based on the type of education (telephone, theory based, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multiparous), follow-up period, region, study quality, and setting (hospital/health centers).


### 2.5. Data Extraction

The titles and abstracts of the eligible studies were independently extracted and screened by two authors (AM and SY), and duplicates were also removed. After providing the full texts of the studies, data extraction was done using a structured form included the name of the author, year of publication, location of study, type of intervention, the time of education, setting, participants, lengths and frequencies of sessions, the comparison group, sample size, measurement instrument, and results. Disagreements of the extractors were resolved by discussion or consultation with the third person.


### 2.6. Quality Assessment

Quality and risk of bias appraisal was conducted based on the guidelines of Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials [17]. 31 studies were considered having low risk of bias (Figure 2).


### 2.7. Analysis

RevMan Software Version 5 was used for analyses. Mean differences were used to find the effect for quantitative data. The heterogeneity of the studies was assessed usingI-squared. Due to the high heterogeneity (I2 > 50%), the random effect was used instead of the fixed effect. The subgroup analysis was done based on the type of education (telephone, theory based, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multiparous), setting (hospital/health center), follow-up period, region, and study quality. Publication bias was assessed using the funnel plot, and Egger’s and Begg’s tests (Figure 3).Figure 3
Inverted symmetrical funnel plot for showing publication bias.


## 2.1. Search Strategy and Data Sources

The English and Persian electronic databases including Medline, Embase, Cochrane Database of Systematic Reviews (CDSR), PubMed, Web of Science, Scopus, CINAHL, Sid, IRANDOC, and Mag-Iran were systematically searched for studies published from 2005 to December 2020 using the following search strategies in accordance with the Mesh browser keywords and free-text words: (Feeding∗OR Breast∗OR Breastfeeding OR “Breast Milk” OR “Human Milk” OR “Breast Milk” OR Lactation OR “Milk Secretion” OR Colostrum OR “Exclusive Breastfeeding”) AND (Pregnancy OR Gestation OR “Pregnant Woman”) AND (Postpartum OR Puerperium) AND (“Self-Efficacy” OR “Self-confidence” OR “Self-concept”) AND (Education∗ OR “Health Education” OR Instruction∗OR Training) AND (“randomized controlled trial” OR “controlled clinical trial” OR randomized∗ OR randomly∗ OR trial∗ OR groups). Moreover, reference lists of the identified articles were screened. The PRISMA checklist (Figure 1) was used for reporting the search result [16]. We used a search strategy, which has been developed in Medline and adapted for other databases. We also used manual approaches, in particular, hand-searching and perusing reference lists of articles to find additional studies for systematic review. Various grey literature databases (such as Open Grey SIGLE, NTIS, Global Index Medicus (GIM), Google Scholar, World Cat, UW Libraries Search), theses, and dissertations, as well as conference proceedings, were assessed for collecting unpublished data. This study was not registered in the PROSPRO database. This meta-analysis was performed and reported in adherence with Preferred Reporting Items for Systematic Reviews and Meta-Analysis.Figure 2
The results of Cochrane risk of bias tool for the evaluation of clinical trial quality.


## 2.2. Inclusion Criteria

The studies with the following criteria were included: (1) healthy mothers with healthy baby, (2) randomized controlled trials (RCTs) with at least two groups (control and intervention) that aimed to measure mother’s BSE, (3) various forms of breastfeeding education (for example, didactic teaching session, face to face, indirect, individual, group, peer support, and workshop) combined with or without other interventions, (4) comparison groups were assigned to usual care and standard care, and (5) study published from Juan 2005 to December 2020 with restricted English and Persian. Due to the fact that the review of interventions in the last 15 years is critical for developing breastfeeding promotion strategy, the period for searching for articles in this review is limited to 2005–2020 years.


## 2.3. Exclusion Criteria

The studies with the following criteria were excluded: (1) the mothers with chronic/systemic disease, parents with preterm baby with/without admitted at NICU ward, and complication in the breast, such as mastitis, (2) a quasi-experimental study, meta-analysis, and cross-sectional and observational studies, (3) noneducational intervention such as kangaroo mother care, motivational interview, psychoeducational counseling approach, and relaxation tone, and (4) randomized controlled trials (RCTs) that measured the mothers’ knowledge or practice of breastfeeding, or breastfeeding initiation or duration.


## 2.4. Outcome

In this study, the main outcome was breastfeeding self-efficacy. The subgroup analysis was done based on the type of education (telephone, theory based, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multiparous), follow-up period, region, study quality, and setting (hospital/health centers).


## 2.5. Data Extraction

The titles and abstracts of the eligible studies were independently extracted and screened by two authors (AM and SY), and duplicates were also removed. After providing the full texts of the studies, data extraction was done using a structured form included the name of the author, year of publication, location of study, type of intervention, the time of education, setting, participants, lengths and frequencies of sessions, the comparison group, sample size, measurement instrument, and results. Disagreements of the extractors were resolved by discussion or consultation with the third person.


## 2.6. Quality Assessment

Quality and risk of bias appraisal was conducted based on the guidelines of Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials [17]. 31 studies were considered having low risk of bias (Figure 2).


## 2.7. Analysis

RevMan Software Version 5 was used for analyses. Mean differences were used to find the effect for quantitative data. The heterogeneity of the studies was assessed usingI-squared. Due to the high heterogeneity (I2 > 50%), the random effect was used instead of the fixed effect. The subgroup analysis was done based on the type of education (telephone, theory based, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multiparous), setting (hospital/health center), follow-up period, region, and study quality. Publication bias was assessed using the funnel plot, and Egger’s and Begg’s tests (Figure 3).Figure 3
Inverted symmetrical funnel plot for showing publication bias.


## 3. Results

The current study was updated until December 2020. A total of 1919 articles were extracted in the primary search based on the search strategy from the following databases: Scopus (129), ISI (515), PubMed (750), Mag-Iran (221), Cochrane (208), and other sources (96). Then, we excluded 640 duplicate articles, 1189 in the title and abstract review, and finally, 47 articles after the full-text review. Four papers had the inclusion criteria, we decided to exclude them from this analysis because one was a conference abstract, two papers had non-English language, and one paper due to lack of reporting the mean of self-efficacy, and we did not receive usable data from the author. A total of 40 articles with 5743 subjects that met the criteria for inclusion were retrieved in this systematic review. All extracted articles were published in Persian or English. The quality assessment of articles was performed by two reviewers, independently. A flowchart of the extracted articles and selection procedure is shown in Figure1.


### 3.1. Characteristics of Included Studies

The characteristics of the 40 RCT studies included in the analysis are summarized in Figure2. Of these, significant increases (p<0.05) in BSE were reported in 26 of the included studies, which received breastfeeding education, and 14 studies reported no effect of education on BSE. Regarding the format of classes, 12 studies were based on group education that seven of them were based on theory. In 19 studies, educational tools such as booklets, pamphlets, video, and fillip cart were used for education. Moreover, women in 20 studies were educated with phone messages or telephone calling for follow-up. Based on the timing of education, the majority of interventions (31 studies) were done during pregnancy. The time of postpartum follow-up was varied at discharge to 24 weeks after childbirth. Regarding the region of the study, 18 studies were conducted in Iran and 2 studies were in Australia and Canada. One study was conducted in 9 countries including Croatia, Denmark, Hong Kong, Iraq, Japan, Spain, Thailand, and Turkey. The five and four study was conducted in the USA and Brazil, respectively. Regarding the study quality, one study had a score of 4, eight studies had score 5, twenty-one studies had score 6, four studies had score 7, and six studies had a score of 8. In all studies, self-efficacy was measured using Dennis breastfeeding self-efficacy (Table 1).Table 1
Summary of studies of the association between educational intervention and breastfeeding self-efficacy.
Author, year (location)Study designGroups (n)Participants and settingTime and format of classesInterventionFollow-up periodTools and outcomeResultsAli et al. Iran [18]RCTsGroup 1: intervention,n = 95/100Group 2: intervention, n = 93/100Group 3: control, n = 95/100Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1: one session, direct face-to-face educational program (20 min)Group 2: one session, indirect educational program using video CD + pamphlet (30 min)Group 3: routine careUp to 3 months after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)Three months after childbirth, a significant difference was observed between the three groups in the mean of breastfeeding self-efficacy (p<0.001). But there was not a significant difference between each intervention groups compared to control group (p>0.05).Heydari et al. Iran [19]RCTsGroup 1: intervention,n = 33/35Group 2: control, n = 32/35Healthy primiparous womenSetting: childbirth preparation classesPregnancy (group class)Telephone = yesTheory = noGroup1: one session, direct face-to-face educational program (45–60 min) +telegram chat up to 4 months after child birthGroup 2: routine careUp to four months after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Four months after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Azhari et al. Iran [20]RCTsGroup 1: intervention,n = 45Group 2: intervention, n = 45Group 3: control, n = 46Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1: one session direct face-to-face educational program (20–40 min)Group 2: one session indirect educational program using the imagesGroup 3: routine care1, 4, and 8 weeks after childbirthBreastfeeding self-efficacy tools: self-efficacy 14 itemsAfter three-stage follow-up, a significant difference was observed between the three groups in the mean of breastfeeding self-efficacy (p<0.001). The highest mean was for the indirect educational groupGodarzi et al. Iran [21]RCTsGroup 1: intervention,n = 52Group 2: control, n = 55Healthy primiparous womenSetting: public health centerPregnancy (group class)Telephone = noTheory = noGroup 1: two sessions (one session in third trimester and one session after child birth. Peer education method was held using lecture and group discussion approachGroup 2: routine careUp to 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Eight weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Chan et al. Hong Kong [22]RCTsGroup 1: intervention,n = 35/35Group 2: control, n = 36/36Healthy primiparous womenSetting: hospitalPregnancy (group class)Telephone = yesTheory = yesGroup1: one session a self-efficacy-based breastfeeding, educational program was held as a workshop + two telephone call after childbirth (30–60 mn)Group 2: routine careUp to 2 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Two weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.01).Ansari et al. Iran [23]RCTsGroup 1: intervention,n = 60/65Group 2: control, 60/65Healthy pregnancySetting: public health centerPregnancy (individual class)Telephone = yesTheory = yesGroup 1: two-session self-efficacy-based educational program with two-day interval for two hours + phone callsGroup 2: routine careOne month after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)One month after childbirth was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.001).Antoñanzas-Baztán et al. Spain [11]RCTsGroup 1: interventionn = 57/59Group 2: control, n = 55/59Healthy pregnancySetting: hospitals and community centerPregnancy (group class)Telephone = yesTheory = noGroup 1: three-session educational program was held. In 28–39 gestational weeks, before discharge, and phone call 48–72 hours after childbirthGroup 2: usual care4 and 8 weeks and 6 months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there wasno significant difference between the two groups on BSES (p>0.05).Piro and Ahmed Iraq [24]RCTsGroup 1: intervention,n = 52/65Group 2: control, n = 54/65Healthy pregnancySetting: public health centerPregnancy (group class)Telephone = noTheory = yesGroup 1: two-session self-efficacy-based educational program was held with two-day interval, each session lasting for 60–90 min + booklet + videoGroup 2: routine careUp to two months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Two months after childbirth, there was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.001).Mohseni et al. Iran [25]RCTsGroup 1: intervention,n = 33/35Group 2: control, n = 32/35Healthy primiparous womenSetting: public clinics, home visitPregnancy (individual class)Telephone = yesTheory = noGroup 1: 3-session educational program was held per week in theirhouse + an educational pamphlet + one visit home after childbirthGroup 2: routine care1,2, and 6 weeks after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there was a significant difference between the two groups (p<0.001).Rabiepoor et al. Iran [26]RCTsGroup 1: intervention,n = 33Group 2: control, n = 33Healthy pregnancySetting: Public health centerPregnancy (individual class)Telephone = yesTheory = noGroup 1: two-session couple educational program with 4-week interval +telephone call over study time. Training package included prenatal and postnatal care and lactationGroup 2: routine careUp to one month after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)One month after childbirth, there was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.017).Puharić et al. Croatia [27]RCTsGroup 1: intervention,n = 129/136Group 2: intervention, n = 103/128Group 3: control group, n = 123/136Healthy primiparous womenSetting: hospitalsPregnancy (individual class)Telephone = yesTheory = noGroup 1: three-session educational program included breastfeeding and parenting booklet + fourproactive telephone calls (one session in pregnancy and three after delivery, at 2, 6, and 10 weeks)Group 2: one-session educational program included pregnancy booklet + four proactive telephone calls (one in pregnancy and three after delivery, at 2, 6, and 10 weeks)Group 3: routine careUp to 3 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Three months after childbirth, there was a significant diﬀerence between three groups regarding self-efficacy mean (p<0.001).Charoghchian Khorasani et al. Iran [28]RCTsGroup 1: intervention,n = 45Group 2: control, n = 45Healthy primiparous womenSetting: public health centerPregnancy (group class)Telephone = noTheory = yesGroup 1: one-sessionself-efficacy-based educational program was held using lectures, role playing, posters, and CD + health literacyGroup 2: routine careUp to 3 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)Three months after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Vakilian et al. Iran [29]RCTsGroup 1: intervention,n = 65Group 2: control, n = 65Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1:home-based educational program using pamphlet + CDGroup 2: routine careUp to 4 weeksBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Four weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Shariat et al. Iran [12]RCTsGroup 1: intervention,n = 64Group 2: control, n = 65Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = yesTheory = noGroup 1: one-session educational program using pamphlet + CDGroup 2: routine careUp to 6 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)After six months, there wasno significant difference between the two groups on BSES (p>0.05).Rodrigues et al. Brazil [30]RCTsGroup 1: intervention,n = 59/104Group 2: control, n = 40/104Healthy pregnancySetting: hospitalPostpartum period (group class)Telephone = noTheory = noGroup 1: one-session educational program using flip chart (40 min)Group 2: routine care15, 30, 60, 90, and 120 days after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After five-stage follow-up, there was a significant difference between the two groups (p<0.001).Chaves et al. Brazil [31]RCTsGroup 1: intervention,n = 39/66Group 2: control, n = 38/66Healthy pregnancySetting: hospitalPostpartum period (individual class)Telephone = yesTheory = noGroup 1: one-session face-to-face educational program + threetelephone calls in 7, 15, and 30 days after discharge (70 min)Group 2: routine care2 and 4 months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After two months, there wasno significant difference between the two groups on BSES (p>0.05). After four months, there was a significant difference between the groups (p<0.01).Dodt et al. Brazil [32]RCTsGroup 1: intervention,n = 54/101Group 2: control, n = 42/100Healthy pregnancySetting: hospitalPostpartum period (individual class)Telephone = yes Theory = noGroup 1: three-session educational program using flip chart in 6 hours postpartum, before discharge, and 2 months after child birth by telephone contactGroup 2: routine careUp to 2 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After two months, there was a significant difference between the two groups (p<0.03).Srinivas et al. USA [33]RCTsGroup 1: intervention,n = 50/63Group 2: control, n = 53/63Healthy pregnancySetting: hospitalPregnancy (individual class)Telephone = yesTheory = noGroup 1: 11-session peer educational program was held, one session 28th weeks of pregnancy, one session within 3 to 5 days after delivery, weekly to 1 month, every 2 weeks up to 3 months, and once at 4 months using telephone callGroup 2: routine careUp to 6 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After six weeks, there wasno significant difference between the two groups on BSES (p>0.05).Nekavand et al. Iran [34]RCTsGroup 1: intervention,n = 50Group 2: control, n = 50Healthy primiparous womenSetting: HospitalPostpartum period (individual class)Telephone = noTheory = noGroup 1: one-session educational program within 5 hours after child birth + bookletGroup 2: routine careUp to one monthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)One month after childbirth, there wasno significant difference between the two groups on BSES (p>0.05).Kronborg et al. Denmark [35]RCTsGroup 1: intervention,n = 582/603Group 2: control, 575/590Healthy primiparous womenSetting: hospitalPregnancy (couple group class)Telephone = noTheory = noGroup 1: one-session educational program was held + lectures and discussions + shown a film for 9 hoursGroup 2: routine careUp to six weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After six weeks, there wasno significant difference between the two groups on BSES (p>0.05).Javorski et al. Brazil [36]RCTsGroup 1: intervention,n = 56/66Group 2: control, 56/66Healthy pregnancySetting: basic health unitsPregnancy (individual class)Telephone = noTheory = noGroup 1: educational program was held using flip chart included picture and textGroup 2: routine care2, 4, and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 2, 4, and 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Araban et al. Iran [10]RCTsGroup 1: intervention 56/60Group 2: control, n = 54/60Healthy primiparous womenSetting: prenatal clinicsPregnancy (group class)Telephone = noTheory = yesGroup 1: two-session group-based educational program was held + booklet and images + sending biweekly text messages up to 8 weeks after childbirthGroup 2: routine careUp to 8 weeksBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Harris-Luna and Badr. California [37]RCTsGroup 1: intervention,n = 31Group 2: control, n = 30Healthy pregnancySetting: obstetric clinicPregnancy (individual class)Telephone = yesTheory = noGroup 1: bilingual Spanish-English educational program was held in three sessions (2 hours) +telephone support weekly for the first 4 weeks and then biweekly for up to 12 weeks after child birthGroup 2: routine careUp to 12 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 12 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Mizrak et al. Turkey [38]RCTsGroup 1: intervention,n = 45Group 2: control, n = 45Healthy primiparous womenSetting: health centersPregnancy (group class)Telephone = yesTheory = yesGroup 1: two educational programs were held in a week using video (90–80 min) + home visit in 1, 4, and 8 weeks or telephone callGroup 2: standard care1, 4, and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 1, 4, and 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).McQueen et al. Toronto [39]RCTsGroup 1: intervention,n = 61/68Group 2: control, n = 73/81Healthy primiparous womenSetting: hospitalPostpartum period (individual class)Telephone = yesTheory = yesGroup 1: two-session educational program based on self-efficacy theory was conducted in hospital, and one session was conducted by telephone within 1 week of discharge from hospitalGroup 2: standard care4 and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 4 and 8 weeks, there wasno significant difference between the two groups on BSES (p>0.05).Prasitwattanaseree et al. Thailand [40]RCTsGroup 1: intervention,n = 41/48Group 2: control, n = 42/49Healthy primiparous womenSetting: hospitalPregnancy (individual class)Telephone = yesTheory = noGroup 1: twelve educational programs were held (2 sessions during pregnancy per week + 1, 2, and 3 days after birth + 7 days, 1 month, 6 weeks, and 3 and 6 months at home with telephone callGroup 2: usual careAt discharge and 6 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)At discharge, there wasno significant difference between the two groups on BSES (p>0.05). After 6 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Moudi et al. Iran [41]RCTsGroup 1: Intervention,n = 32/36Group 2: intervention, n = 32/36Group 3: control, n = 31/32Healthy primiparous womenSetting: health centersPregnancy (individual class)Telephone = yesTheory = noGroup 1: peer support training was held in four sessions. One session was face to face in 36–38 weeks, and three sessions were done using telephone call in 1, 2, and 3 weeks after child birthGroup 2: provider training was held in four sessions. Two sessions were face to face, and the next two sessions were held in the 1 and 3 weeks after child birth by telephone callGroup 3: standard care8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks, there wasno significant difference between the three groups on BSES (p>0.05). BSES at the end of the eighth week was significantly increased in peer support compared to provider groups (p<0.05).Saljughi et al. Iran [42]RCTsGroup 1: intervention,n = 37Group 2: control, n = 37Healthy pregnancySetting: health centersPregnancy group class)Telephone = noTheory = noGroup 1: one-session educational program using role playing approach (90 min)Group 2: routine careOne week and 1 month after child birthBreastfeeding self-efficacy tools: breastfeeding self-efficacy (14 items)After 1 week and 1 month, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Khorshidifard et al. Iran [43]RCTsGroup 1: intervention,n = 88Group 2: intervention, n = 88Group 3: control, n = 88Healthy primiparous womenSetting: health centersPregnancy individually + small group class)Telephone = noTheory = noGroup 1: direct face-to face-individually educational program in three sessions using lecture, discussion, and role playing approachGroup 2: small group educational program was held in three sessionsGroup 3: routine careAfter last session of education and after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After last session of education and after child birth, there was a significant difference between three groups in the mean of breastfeeding self-efficacy (p<0.001).Otsuka et al. Japan [44]RCTsGroup 1: intervention,n = 136Group 2: intervention n = 239Group 3: control, n = 140Group 4: control, n = 266Healthy pregnancySetting: baby-friendly hospitals (BFHs)Pregnancy (individual class)Telephone = noTheory = yesGroups 1 and 2: self-efficacy workbook in six sections was completed by womenGroups 3 and 4: routine careAt discharge and 4 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After controlling for potential confounding factors and time, the intervention resulted in an increase in the BSES-SF total score through 4 weeks postpartum in BFHs (p<0.001), but it had no effect on breastfeeding self-efficacy p<0.05).Khosravan, et al. Iran [45]RCTsGroup 1: interventionn = 40Group 2: control n = 40Healthy primiparous womenSetting: hospitalPregnancy (individual class)Telephone = noTheory = yesGroup 1: six-session educational program using problem solvingGroup 2: routine careAfter last session of education and 3 months after child birthTools: Dennis breastfeeding self-efficacy (33 items)After last session of education and after child birth, there was a significant difference between two groups in the mean of breastfeeding self-efficacy (p<0.001).Salehi et al. Iran [46]RCTsGroup 1: interventionn = 70Group 2: intervention n = 70Group 3: control n = 70Healthy primiparous womenSetting: health centerPregnancy (group class)Telephone = yesTheory = noGroup 1: amotivational interview was held preweek in five sessions + three sessions of telephone counseling in 3–5 days, 1 and 4 months after discharge + telegram chatGroup 2: one session of lecture (2 hours) + question and answer panelGroup 3: routine care2, 4, and 6 months after child birthTools: Dennis breastfeeding self-efficacy (14 items)In the lecture and control group, there was a significant increase until the second month (p<0.001), and self-efficacy decreased in months 4 and 6 compared to the second months (p>0.05).Lutenbacher et al. USA [47]RCTGroup 1: interventionn = 76Group 2: control n = 69Participant healthy pregnancySetting: health centerPregnancy individual classTelephone = yesTheory = noGroup 1: educational program based on the maternal infant health outreach worker (MIHOW) model by peer mentors (40 h)Group 2: routine care (a minimal education intervention MEI)2 weeks and 2 and 6 months after childbirthTools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there was a significant difference between the two groups (p<0.001).Mesters et al. Netherland [48]RCTsGroup 1: intervention,n = 44Group 2: control, n = 45Healthy pregnancySetting: health centerPregnancy (individual class)Telephone = noTheory = yesGroup 1: four-session educational program using atheory-based booklet and pre- and postnatal home visits (2 sessions of face to face and one session as a home visit in prenatal + 1 session home visit in postnatal)Group 2: routine care3 months after child birthTools: Dennis breastfeeding self-efficacy (14 items)A statistically significant difference was observed between 8 months of pregnancy and 3 months postpartum in which self-efficacy expectation increased in both groups (p<0.05).Edwards et al. USA [49]RCTsGroup 1: intervention,n = 7Group 2: control, n = 8Healthy primiparous womenSetting: hospitalPregnancy individualTelephone = noTheory = noGroup 1: educational program using a computer agentGroup 2: usual careAt dischargeTools: Dennis breastfeeding self-efficacy (14 items)At discharge,no significant difference was observed between the three groups on BSES (p>0.05).Noel-Weiss et al. Canada [50]RCTsGroup 1: intervention,n = 41Group 2: control, n = 39Healthy primiparous womenSetting: hospitalPostpartum group classTelephone = yesTheory = yesGroup 1: the intervention was a 2.5-hour prenatal breastfeeding workshop designed using Bandura’s theory of self-efficacy and adult learning principlesGroup 2: routine care4 and 8 weeks after childbirthTools: Dennis breastfeeding self-efficacy (14 items)After 4 weeks, there was a significant difference between the two groups (p=0.02). After 8 weeks, no significant difference was observed between the two groups (p>0.05).Hauck et al. Australia [51]RCTsGroup 1: intervention,n = 123Group 2: control, n = 123Healthy primiparous womenSetting: hospitalPregnancy individual classTelephone = noTheory = noGroup 1: the intervention was a 3-hour prenatal breastfeeding workshop + breastfeeding journal Bandura’s theoryGroup 2: routine care12 weeks after child birthTools: Dennis breastfeeding self-efficacy (33 items)After 12 weeks,no significant difference was observed between the two groups (p>0.05).Mehrabi et al. Iran [52]RCTsGroup 1: intervention,n = 60Group 2: control, n = 60Healthy womenSetting: health centerPregnancy individual classTelephone = yesTheory = noGroup 1: mobile messaging on breastfeeding self-efficacy educational programGroup 2: routine careAfter 2 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After 2 weeks, there was a significant difference between the two groups(p=0.001).Schlickau, Nebraska, USA [53]RCTsGroup 1: intervention,n = 33Group 2: control, n = 15Healthy primiparous womenSetting: healthPregnancy individualGroup 1: one-session educational program based onPender’s health promotion model (HPM) and support after child birth during the follow-up periodGroup 2: standard care2 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items) 2 weeksAfter 2 weeks, there was a significant difference between the two groups(p=0.001).Gallegos et al. Australia [54]RCTsGroup 1: intervention,n = 114Group 2: control, n = 86Healthy womenSetting: health centerPostpartum group classTelephone = yesTheory = noGroup 1: weekly educational massage for eight weeks + Facebook page involvementGroup 2: standard care8 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks,no significant difference was observed between the two groups (p>0.05).Abuidhail et.al. Jordan [55]A prospective RCTGroup 1: intervention,n = 56Group 2: control, n = 56Participant: healthy pregnancyPregnancy (individual class)Group 1: two-session educational program was held using videos and images. It can be accessed bywebsite with connecting Internet by computers or smart phones or any device + one notification text massage with mobile 3 days after last educational programGroup 2: routine careUp two weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After adjusting for preintervention scores, there wasno significant difference between the experimental and control groups on postintervention scores on BSES (p=0.22).


### 3.2. Main Results

After quality assessment of studies, the results of 40 studies were included in the meta-analysis. The overall results demonstrated that educational intervention has a positive impact on BSE (pooled SMD = 1.20; 95% CI = 0.75–1.64,p value <0.001) (Figure 4). The high heterogeneity was seen among included studies (I2 = 98%, p<0.001) (Figure 4). Egger’s and Begg’s tests were conducted to explore the publication bias in our meta-analysis (Figure 3). The funnel plot in Figure 3 shows symmetrical funnel plots among studies. There was no significant publication bias in this study based on Egger’s and Begg’s tests (p=0.790 and p=0.107, respectively).Figure 4
Forest plot of studies that investigated the influence of breastfeeding education on the self-efficacy of breastfeeding.


### 3.3. Subgroup Analysis

The subgroup analyses were conducted based on the type of education (theory based, telephone, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multi), follow-up period, region, study quality, and setting (hospital/health centers). Our findings showed that the effect of theory-based education on BSE (SMD = 2.56; CI = 1.80–3.32) was more than that of non-theory-based education (SMD = 0.64; CI = 0.11–1.17), breastfeeding education during pregnancy (SMD = 1.76; 95% CI = 1.08–2.26) was more effective compared with the postpartum period (SMD = 0.08; 95% CI = -0.48–0.65), the use of phone for training or follow-up (SMD = 0.80; 95% CI = 0.04–1.56) was less effective compared with direct education (SMD = 1.57; 95% CI = 1–2.14), the effect of education on primiparous (SMD = 1.21; 95% CI = 0.57–1.86) was more than that of the multiparous (SMD = 1.09; 95% CI = 0.45–1.74), breastfeeding education in health centers (SMD = 2.31; 95% CI = 1.46–3.17) was more effective than in the hospital setting (SMD = 0.36; 95% CI = −0.15–0.87), the effect of education in Asia (SMD = 1.70; 95% CI = 1.21–2.20) was more than that in the other regions (SMD = 0.46; 95% CI = −0.30–1.22), the effect of education in higher-quality studies (SMD = 1.52; 95% CI = 1.01–2.04) was more than that in the lower-quality studies (SMD = 0.10; 95% CI = −0.61–0.81), the group education (SMD = 1.48; 95% CI = 0.61–2.35) was more effective on BSE than the individual education (SMD = 0.99; 95% CI = 0.46–1.52), but the heterogeneity of all subgroups was high. The subgroup analyses based on the follow-up period showed that education in the first week of postpartum had most effect on BSE (SMD = 1.49; 95% CI 1.36–1.61) than the others. However, the heterogeneity of studies in 6 weeks was least rate (I2 = 77.4%) (Table 2).Table 2
The result of subgroup analysis on the breastfeeding self-efficacy.
SubgroupsSMD (95% CI)No. of studyI2Primiparous1.21 (0.57–1.86)2498.5Multiparous1.09 (0.45–1.74)1697.6Group1.48 (0.61–2.35)1598.8Individual0.99 (0.46–1.52)2597.7Phone0.80 (0.04–1.56)2198.3Direct education1.57 (1.0–2.14)1998.1Theory2.56 (1.80–3.32)1196.9No theory0.64 (0.11–1.17)2998.3Postpartum0.08 (−0.48–0.65)1196.2Pregnancy1.67 (1.08–2.26)2998.5Hospital0.36 (−0.15–0.87)2198.0Health center2.31 (1.46–3.17)1998.2Asia1.70 (1.21–2.20)2397.1Others0.46 (−0.30–1.22)1798.6Higher-quality studies0.10 (−0.61–0.81)995.6Lower-quality studies1.52 (1.01–2.04)3198.0At discharge up to 1 week1.49 (1.36–1.61)996.92 weeks1.18 (1.01–1.35)785.64 weeks0.64 (0.54–0.73)1386.56 weeks0.61 (0.50–0.73)477.48 weeks0.53 (0.42–0.63)1697.812 weeks−0.35 (−0.50–0.21)899.216 weeks0.87 (0.62–1.13)498.824 weeks0.93 (0.72–1.14)498.9


### 3.4. Sensitive Analysis

For sensitive analysis, we excluded 9 studies that have low quality. The sensitive analysis showed that there were no obvious changes after excluding the studies (Figure5). Therefore, our results were reliable.Figure 5
Sensitive analysis based on quality of studies.


## 3.1. Characteristics of Included Studies

The characteristics of the 40 RCT studies included in the analysis are summarized in Figure2. Of these, significant increases (p<0.05) in BSE were reported in 26 of the included studies, which received breastfeeding education, and 14 studies reported no effect of education on BSE. Regarding the format of classes, 12 studies were based on group education that seven of them were based on theory. In 19 studies, educational tools such as booklets, pamphlets, video, and fillip cart were used for education. Moreover, women in 20 studies were educated with phone messages or telephone calling for follow-up. Based on the timing of education, the majority of interventions (31 studies) were done during pregnancy. The time of postpartum follow-up was varied at discharge to 24 weeks after childbirth. Regarding the region of the study, 18 studies were conducted in Iran and 2 studies were in Australia and Canada. One study was conducted in 9 countries including Croatia, Denmark, Hong Kong, Iraq, Japan, Spain, Thailand, and Turkey. The five and four study was conducted in the USA and Brazil, respectively. Regarding the study quality, one study had a score of 4, eight studies had score 5, twenty-one studies had score 6, four studies had score 7, and six studies had a score of 8. In all studies, self-efficacy was measured using Dennis breastfeeding self-efficacy (Table 1).Table 1
Summary of studies of the association between educational intervention and breastfeeding self-efficacy.
Author, year (location)Study designGroups (n)Participants and settingTime and format of classesInterventionFollow-up periodTools and outcomeResultsAli et al. Iran [18]RCTsGroup 1: intervention,n = 95/100Group 2: intervention, n = 93/100Group 3: control, n = 95/100Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1: one session, direct face-to-face educational program (20 min)Group 2: one session, indirect educational program using video CD + pamphlet (30 min)Group 3: routine careUp to 3 months after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)Three months after childbirth, a significant difference was observed between the three groups in the mean of breastfeeding self-efficacy (p<0.001). But there was not a significant difference between each intervention groups compared to control group (p>0.05).Heydari et al. Iran [19]RCTsGroup 1: intervention,n = 33/35Group 2: control, n = 32/35Healthy primiparous womenSetting: childbirth preparation classesPregnancy (group class)Telephone = yesTheory = noGroup1: one session, direct face-to-face educational program (45–60 min) +telegram chat up to 4 months after child birthGroup 2: routine careUp to four months after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Four months after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Azhari et al. Iran [20]RCTsGroup 1: intervention,n = 45Group 2: intervention, n = 45Group 3: control, n = 46Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1: one session direct face-to-face educational program (20–40 min)Group 2: one session indirect educational program using the imagesGroup 3: routine care1, 4, and 8 weeks after childbirthBreastfeeding self-efficacy tools: self-efficacy 14 itemsAfter three-stage follow-up, a significant difference was observed between the three groups in the mean of breastfeeding self-efficacy (p<0.001). The highest mean was for the indirect educational groupGodarzi et al. Iran [21]RCTsGroup 1: intervention,n = 52Group 2: control, n = 55Healthy primiparous womenSetting: public health centerPregnancy (group class)Telephone = noTheory = noGroup 1: two sessions (one session in third trimester and one session after child birth. Peer education method was held using lecture and group discussion approachGroup 2: routine careUp to 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Eight weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Chan et al. Hong Kong [22]RCTsGroup 1: intervention,n = 35/35Group 2: control, n = 36/36Healthy primiparous womenSetting: hospitalPregnancy (group class)Telephone = yesTheory = yesGroup1: one session a self-efficacy-based breastfeeding, educational program was held as a workshop + two telephone call after childbirth (30–60 mn)Group 2: routine careUp to 2 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Two weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.01).Ansari et al. Iran [23]RCTsGroup 1: intervention,n = 60/65Group 2: control, 60/65Healthy pregnancySetting: public health centerPregnancy (individual class)Telephone = yesTheory = yesGroup 1: two-session self-efficacy-based educational program with two-day interval for two hours + phone callsGroup 2: routine careOne month after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)One month after childbirth was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.001).Antoñanzas-Baztán et al. Spain [11]RCTsGroup 1: interventionn = 57/59Group 2: control, n = 55/59Healthy pregnancySetting: hospitals and community centerPregnancy (group class)Telephone = yesTheory = noGroup 1: three-session educational program was held. In 28–39 gestational weeks, before discharge, and phone call 48–72 hours after childbirthGroup 2: usual care4 and 8 weeks and 6 months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there wasno significant difference between the two groups on BSES (p>0.05).Piro and Ahmed Iraq [24]RCTsGroup 1: intervention,n = 52/65Group 2: control, n = 54/65Healthy pregnancySetting: public health centerPregnancy (group class)Telephone = noTheory = yesGroup 1: two-session self-efficacy-based educational program was held with two-day interval, each session lasting for 60–90 min + booklet + videoGroup 2: routine careUp to two months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Two months after childbirth, there was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.001).Mohseni et al. Iran [25]RCTsGroup 1: intervention,n = 33/35Group 2: control, n = 32/35Healthy primiparous womenSetting: public clinics, home visitPregnancy (individual class)Telephone = yesTheory = noGroup 1: 3-session educational program was held per week in theirhouse + an educational pamphlet + one visit home after childbirthGroup 2: routine care1,2, and 6 weeks after childbirthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there was a significant difference between the two groups (p<0.001).Rabiepoor et al. Iran [26]RCTsGroup 1: intervention,n = 33Group 2: control, n = 33Healthy pregnancySetting: Public health centerPregnancy (individual class)Telephone = yesTheory = noGroup 1: two-session couple educational program with 4-week interval +telephone call over study time. Training package included prenatal and postnatal care and lactationGroup 2: routine careUp to one month after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)One month after childbirth, there was a significant diﬀerence between two groups regarding self-efficacy mean (p<0.017).Puharić et al. Croatia [27]RCTsGroup 1: intervention,n = 129/136Group 2: intervention, n = 103/128Group 3: control group, n = 123/136Healthy primiparous womenSetting: hospitalsPregnancy (individual class)Telephone = yesTheory = noGroup 1: three-session educational program included breastfeeding and parenting booklet + fourproactive telephone calls (one session in pregnancy and three after delivery, at 2, 6, and 10 weeks)Group 2: one-session educational program included pregnancy booklet + four proactive telephone calls (one in pregnancy and three after delivery, at 2, 6, and 10 weeks)Group 3: routine careUp to 3 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Three months after childbirth, there was a significant diﬀerence between three groups regarding self-efficacy mean (p<0.001).Charoghchian Khorasani et al. Iran [28]RCTsGroup 1: intervention,n = 45Group 2: control, n = 45Healthy primiparous womenSetting: public health centerPregnancy (group class)Telephone = noTheory = yesGroup 1: one-sessionself-efficacy-based educational program was held using lectures, role playing, posters, and CD + health literacyGroup 2: routine careUp to 3 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)Three months after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Vakilian et al. Iran [29]RCTsGroup 1: intervention,n = 65Group 2: control, n = 65Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = noTheory = noGroup 1:home-based educational program using pamphlet + CDGroup 2: routine careUp to 4 weeksBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)Four weeks after childbirth, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Shariat et al. Iran [12]RCTsGroup 1: intervention,n = 64Group 2: control, n = 65Healthy primiparous womenSetting: hospitalPostpartum (individual class)Telephone = yesTheory = noGroup 1: one-session educational program using pamphlet + CDGroup 2: routine careUp to 6 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (33 items)After six months, there wasno significant difference between the two groups on BSES (p>0.05).Rodrigues et al. Brazil [30]RCTsGroup 1: intervention,n = 59/104Group 2: control, n = 40/104Healthy pregnancySetting: hospitalPostpartum period (group class)Telephone = noTheory = noGroup 1: one-session educational program using flip chart (40 min)Group 2: routine care15, 30, 60, 90, and 120 days after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After five-stage follow-up, there was a significant difference between the two groups (p<0.001).Chaves et al. Brazil [31]RCTsGroup 1: intervention,n = 39/66Group 2: control, n = 38/66Healthy pregnancySetting: hospitalPostpartum period (individual class)Telephone = yesTheory = noGroup 1: one-session face-to-face educational program + threetelephone calls in 7, 15, and 30 days after discharge (70 min)Group 2: routine care2 and 4 months after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After two months, there wasno significant difference between the two groups on BSES (p>0.05). After four months, there was a significant difference between the groups (p<0.01).Dodt et al. Brazil [32]RCTsGroup 1: intervention,n = 54/101Group 2: control, n = 42/100Healthy pregnancySetting: hospitalPostpartum period (individual class)Telephone = yes Theory = noGroup 1: three-session educational program using flip chart in 6 hours postpartum, before discharge, and 2 months after child birth by telephone contactGroup 2: routine careUp to 2 monthsBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After two months, there was a significant difference between the two groups (p<0.03).Srinivas et al. USA [33]RCTsGroup 1: intervention,n = 50/63Group 2: control, n = 53/63Healthy pregnancySetting: hospitalPregnancy (individual class)Telephone = yesTheory = noGroup 1: 11-session peer educational program was held, one session 28th weeks of pregnancy, one session within 3 to 5 days after delivery, weekly to 1 month, every 2 weeks up to 3 months, and once at 4 months using telephone callGroup 2: routine careUp to 6 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After six weeks, there wasno significant difference between the two groups on BSES (p>0.05).Nekavand et al. Iran [34]RCTsGroup 1: intervention,n = 50Group 2: control, n = 50Healthy primiparous womenSetting: HospitalPostpartum period (individual class)Telephone = noTheory = noGroup 1: one-session educational program within 5 hours after child birth + bookletGroup 2: routine careUp to one monthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)One month after childbirth, there wasno significant difference between the two groups on BSES (p>0.05).Kronborg et al. Denmark [35]RCTsGroup 1: intervention,n = 582/603Group 2: control, 575/590Healthy primiparous womenSetting: hospitalPregnancy (couple group class)Telephone = noTheory = noGroup 1: one-session educational program was held + lectures and discussions + shown a film for 9 hoursGroup 2: routine careUp to six weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After six weeks, there wasno significant difference between the two groups on BSES (p>0.05).Javorski et al. Brazil [36]RCTsGroup 1: intervention,n = 56/66Group 2: control, 56/66Healthy pregnancySetting: basic health unitsPregnancy (individual class)Telephone = noTheory = noGroup 1: educational program was held using flip chart included picture and textGroup 2: routine care2, 4, and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 2, 4, and 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Araban et al. Iran [10]RCTsGroup 1: intervention 56/60Group 2: control, n = 54/60Healthy primiparous womenSetting: prenatal clinicsPregnancy (group class)Telephone = noTheory = yesGroup 1: two-session group-based educational program was held + booklet and images + sending biweekly text messages up to 8 weeks after childbirthGroup 2: routine careUp to 8 weeksBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Harris-Luna and Badr. California [37]RCTsGroup 1: intervention,n = 31Group 2: control, n = 30Healthy pregnancySetting: obstetric clinicPregnancy (individual class)Telephone = yesTheory = noGroup 1: bilingual Spanish-English educational program was held in three sessions (2 hours) +telephone support weekly for the first 4 weeks and then biweekly for up to 12 weeks after child birthGroup 2: routine careUp to 12 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 12 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Mizrak et al. Turkey [38]RCTsGroup 1: intervention,n = 45Group 2: control, n = 45Healthy primiparous womenSetting: health centersPregnancy (group class)Telephone = yesTheory = yesGroup 1: two educational programs were held in a week using video (90–80 min) + home visit in 1, 4, and 8 weeks or telephone callGroup 2: standard care1, 4, and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 1, 4, and 8 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).McQueen et al. Toronto [39]RCTsGroup 1: intervention,n = 61/68Group 2: control, n = 73/81Healthy primiparous womenSetting: hospitalPostpartum period (individual class)Telephone = yesTheory = yesGroup 1: two-session educational program based on self-efficacy theory was conducted in hospital, and one session was conducted by telephone within 1 week of discharge from hospitalGroup 2: standard care4 and 8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 4 and 8 weeks, there wasno significant difference between the two groups on BSES (p>0.05).Prasitwattanaseree et al. Thailand [40]RCTsGroup 1: intervention,n = 41/48Group 2: control, n = 42/49Healthy primiparous womenSetting: hospitalPregnancy (individual class)Telephone = yesTheory = noGroup 1: twelve educational programs were held (2 sessions during pregnancy per week + 1, 2, and 3 days after birth + 7 days, 1 month, 6 weeks, and 3 and 6 months at home with telephone callGroup 2: usual careAt discharge and 6 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)At discharge, there wasno significant difference between the two groups on BSES (p>0.05). After 6 weeks, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Moudi et al. Iran [41]RCTsGroup 1: Intervention,n = 32/36Group 2: intervention, n = 32/36Group 3: control, n = 31/32Healthy primiparous womenSetting: health centersPregnancy (individual class)Telephone = yesTheory = noGroup 1: peer support training was held in four sessions. One session was face to face in 36–38 weeks, and three sessions were done using telephone call in 1, 2, and 3 weeks after child birthGroup 2: provider training was held in four sessions. Two sessions were face to face, and the next two sessions were held in the 1 and 3 weeks after child birth by telephone callGroup 3: standard care8 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks, there wasno significant difference between the three groups on BSES (p>0.05). BSES at the end of the eighth week was significantly increased in peer support compared to provider groups (p<0.05).Saljughi et al. Iran [42]RCTsGroup 1: intervention,n = 37Group 2: control, n = 37Healthy pregnancySetting: health centersPregnancy group class)Telephone = noTheory = noGroup 1: one-session educational program using role playing approach (90 min)Group 2: routine careOne week and 1 month after child birthBreastfeeding self-efficacy tools: breastfeeding self-efficacy (14 items)After 1 week and 1 month, a significant difference was observed between the two groups in the mean of breastfeeding self-efficacy (p<0.001).Khorshidifard et al. Iran [43]RCTsGroup 1: intervention,n = 88Group 2: intervention, n = 88Group 3: control, n = 88Healthy primiparous womenSetting: health centersPregnancy individually + small group class)Telephone = noTheory = noGroup 1: direct face-to face-individually educational program in three sessions using lecture, discussion, and role playing approachGroup 2: small group educational program was held in three sessionsGroup 3: routine careAfter last session of education and after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After last session of education and after child birth, there was a significant difference between three groups in the mean of breastfeeding self-efficacy (p<0.001).Otsuka et al. Japan [44]RCTsGroup 1: intervention,n = 136Group 2: intervention n = 239Group 3: control, n = 140Group 4: control, n = 266Healthy pregnancySetting: baby-friendly hospitals (BFHs)Pregnancy (individual class)Telephone = noTheory = yesGroups 1 and 2: self-efficacy workbook in six sections was completed by womenGroups 3 and 4: routine careAt discharge and 4 weeks after child birthBreastfeeding self-efficacy tools: Dennis breastfeeding self-efficacy (14 items)After controlling for potential confounding factors and time, the intervention resulted in an increase in the BSES-SF total score through 4 weeks postpartum in BFHs (p<0.001), but it had no effect on breastfeeding self-efficacy p<0.05).Khosravan, et al. Iran [45]RCTsGroup 1: interventionn = 40Group 2: control n = 40Healthy primiparous womenSetting: hospitalPregnancy (individual class)Telephone = noTheory = yesGroup 1: six-session educational program using problem solvingGroup 2: routine careAfter last session of education and 3 months after child birthTools: Dennis breastfeeding self-efficacy (33 items)After last session of education and after child birth, there was a significant difference between two groups in the mean of breastfeeding self-efficacy (p<0.001).Salehi et al. Iran [46]RCTsGroup 1: interventionn = 70Group 2: intervention n = 70Group 3: control n = 70Healthy primiparous womenSetting: health centerPregnancy (group class)Telephone = yesTheory = noGroup 1: amotivational interview was held preweek in five sessions + three sessions of telephone counseling in 3–5 days, 1 and 4 months after discharge + telegram chatGroup 2: one session of lecture (2 hours) + question and answer panelGroup 3: routine care2, 4, and 6 months after child birthTools: Dennis breastfeeding self-efficacy (14 items)In the lecture and control group, there was a significant increase until the second month (p<0.001), and self-efficacy decreased in months 4 and 6 compared to the second months (p>0.05).Lutenbacher et al. USA [47]RCTGroup 1: interventionn = 76Group 2: control n = 69Participant healthy pregnancySetting: health centerPregnancy individual classTelephone = yesTheory = noGroup 1: educational program based on the maternal infant health outreach worker (MIHOW) model by peer mentors (40 h)Group 2: routine care (a minimal education intervention MEI)2 weeks and 2 and 6 months after childbirthTools: Dennis breastfeeding self-efficacy (14 items)After three-stage follow-up, there was a significant difference between the two groups (p<0.001).Mesters et al. Netherland [48]RCTsGroup 1: intervention,n = 44Group 2: control, n = 45Healthy pregnancySetting: health centerPregnancy (individual class)Telephone = noTheory = yesGroup 1: four-session educational program using atheory-based booklet and pre- and postnatal home visits (2 sessions of face to face and one session as a home visit in prenatal + 1 session home visit in postnatal)Group 2: routine care3 months after child birthTools: Dennis breastfeeding self-efficacy (14 items)A statistically significant difference was observed between 8 months of pregnancy and 3 months postpartum in which self-efficacy expectation increased in both groups (p<0.05).Edwards et al. USA [49]RCTsGroup 1: intervention,n = 7Group 2: control, n = 8Healthy primiparous womenSetting: hospitalPregnancy individualTelephone = noTheory = noGroup 1: educational program using a computer agentGroup 2: usual careAt dischargeTools: Dennis breastfeeding self-efficacy (14 items)At discharge,no significant difference was observed between the three groups on BSES (p>0.05).Noel-Weiss et al. Canada [50]RCTsGroup 1: intervention,n = 41Group 2: control, n = 39Healthy primiparous womenSetting: hospitalPostpartum group classTelephone = yesTheory = yesGroup 1: the intervention was a 2.5-hour prenatal breastfeeding workshop designed using Bandura’s theory of self-efficacy and adult learning principlesGroup 2: routine care4 and 8 weeks after childbirthTools: Dennis breastfeeding self-efficacy (14 items)After 4 weeks, there was a significant difference between the two groups (p=0.02). After 8 weeks, no significant difference was observed between the two groups (p>0.05).Hauck et al. Australia [51]RCTsGroup 1: intervention,n = 123Group 2: control, n = 123Healthy primiparous womenSetting: hospitalPregnancy individual classTelephone = noTheory = noGroup 1: the intervention was a 3-hour prenatal breastfeeding workshop + breastfeeding journal Bandura’s theoryGroup 2: routine care12 weeks after child birthTools: Dennis breastfeeding self-efficacy (33 items)After 12 weeks,no significant difference was observed between the two groups (p>0.05).Mehrabi et al. Iran [52]RCTsGroup 1: intervention,n = 60Group 2: control, n = 60Healthy womenSetting: health centerPregnancy individual classTelephone = yesTheory = noGroup 1: mobile messaging on breastfeeding self-efficacy educational programGroup 2: routine careAfter 2 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After 2 weeks, there was a significant difference between the two groups(p=0.001).Schlickau, Nebraska, USA [53]RCTsGroup 1: intervention,n = 33Group 2: control, n = 15Healthy primiparous womenSetting: healthPregnancy individualGroup 1: one-session educational program based onPender’s health promotion model (HPM) and support after child birth during the follow-up periodGroup 2: standard care2 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items) 2 weeksAfter 2 weeks, there was a significant difference between the two groups(p=0.001).Gallegos et al. Australia [54]RCTsGroup 1: intervention,n = 114Group 2: control, n = 86Healthy womenSetting: health centerPostpartum group classTelephone = yesTheory = noGroup 1: weekly educational massage for eight weeks + Facebook page involvementGroup 2: standard care8 weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After 8 weeks,no significant difference was observed between the two groups (p>0.05).Abuidhail et.al. Jordan [55]A prospective RCTGroup 1: intervention,n = 56Group 2: control, n = 56Participant: healthy pregnancyPregnancy (individual class)Group 1: two-session educational program was held using videos and images. It can be accessed bywebsite with connecting Internet by computers or smart phones or any device + one notification text massage with mobile 3 days after last educational programGroup 2: routine careUp two weeks after child birthTools: Dennis breastfeeding self-efficacy (14 items)After adjusting for preintervention scores, there wasno significant difference between the experimental and control groups on postintervention scores on BSES (p=0.22).


## 3.2. Main Results

After quality assessment of studies, the results of 40 studies were included in the meta-analysis. The overall results demonstrated that educational intervention has a positive impact on BSE (pooled SMD = 1.20; 95% CI = 0.75–1.64,p value <0.001) (Figure 4). The high heterogeneity was seen among included studies (I2 = 98%, p<0.001) (Figure 4). Egger’s and Begg’s tests were conducted to explore the publication bias in our meta-analysis (Figure 3). The funnel plot in Figure 3 shows symmetrical funnel plots among studies. There was no significant publication bias in this study based on Egger’s and Begg’s tests (p=0.790 and p=0.107, respectively).Figure 4
Forest plot of studies that investigated the influence of breastfeeding education on the self-efficacy of breastfeeding.


## 3.3. Subgroup Analysis

The subgroup analyses were conducted based on the type of education (theory based, telephone, and group/individual), time of education (pregnancy/postpartum), participants (primiparous/multi), follow-up period, region, study quality, and setting (hospital/health centers). Our findings showed that the effect of theory-based education on BSE (SMD = 2.56; CI = 1.80–3.32) was more than that of non-theory-based education (SMD = 0.64; CI = 0.11–1.17), breastfeeding education during pregnancy (SMD = 1.76; 95% CI = 1.08–2.26) was more effective compared with the postpartum period (SMD = 0.08; 95% CI = -0.48–0.65), the use of phone for training or follow-up (SMD = 0.80; 95% CI = 0.04–1.56) was less effective compared with direct education (SMD = 1.57; 95% CI = 1–2.14), the effect of education on primiparous (SMD = 1.21; 95% CI = 0.57–1.86) was more than that of the multiparous (SMD = 1.09; 95% CI = 0.45–1.74), breastfeeding education in health centers (SMD = 2.31; 95% CI = 1.46–3.17) was more effective than in the hospital setting (SMD = 0.36; 95% CI = −0.15–0.87), the effect of education in Asia (SMD = 1.70; 95% CI = 1.21–2.20) was more than that in the other regions (SMD = 0.46; 95% CI = −0.30–1.22), the effect of education in higher-quality studies (SMD = 1.52; 95% CI = 1.01–2.04) was more than that in the lower-quality studies (SMD = 0.10; 95% CI = −0.61–0.81), the group education (SMD = 1.48; 95% CI = 0.61–2.35) was more effective on BSE than the individual education (SMD = 0.99; 95% CI = 0.46–1.52), but the heterogeneity of all subgroups was high. The subgroup analyses based on the follow-up period showed that education in the first week of postpartum had most effect on BSE (SMD = 1.49; 95% CI 1.36–1.61) than the others. However, the heterogeneity of studies in 6 weeks was least rate (I2 = 77.4%) (Table 2).Table 2
The result of subgroup analysis on the breastfeeding self-efficacy.
SubgroupsSMD (95% CI)No. of studyI2Primiparous1.21 (0.57–1.86)2498.5Multiparous1.09 (0.45–1.74)1697.6Group1.48 (0.61–2.35)1598.8Individual0.99 (0.46–1.52)2597.7Phone0.80 (0.04–1.56)2198.3Direct education1.57 (1.0–2.14)1998.1Theory2.56 (1.80–3.32)1196.9No theory0.64 (0.11–1.17)2998.3Postpartum0.08 (−0.48–0.65)1196.2Pregnancy1.67 (1.08–2.26)2998.5Hospital0.36 (−0.15–0.87)2198.0Health center2.31 (1.46–3.17)1998.2Asia1.70 (1.21–2.20)2397.1Others0.46 (−0.30–1.22)1798.6Higher-quality studies0.10 (−0.61–0.81)995.6Lower-quality studies1.52 (1.01–2.04)3198.0At discharge up to 1 week1.49 (1.36–1.61)996.92 weeks1.18 (1.01–1.35)785.64 weeks0.64 (0.54–0.73)1386.56 weeks0.61 (0.50–0.73)477.48 weeks0.53 (0.42–0.63)1697.812 weeks−0.35 (−0.50–0.21)899.216 weeks0.87 (0.62–1.13)498.824 weeks0.93 (0.72–1.14)498.9


## 3.4. Sensitive Analysis

For sensitive analysis, we excluded 9 studies that have low quality. The sensitive analysis showed that there were no obvious changes after excluding the studies (Figure5). Therefore, our results were reliable.Figure 5
Sensitive analysis based on quality of studies.


## 4. Discussion

The results from the pooled RCT data highlight the positive impact of educational intervention on the self-efficacy of breastfeeding compared with the usual/standard care. However, substantial heterogeneity was high across the included studies. The subgroup analysis showed that the educational intervention was based on theory, group class format, direct method education, doing during pregnancy, on primiparous women, and health center setting, and the Asian region has a more effect on BSE than the others. The time of postpartum follow-up for evaluating the effect of educational intervention on BSE was a considerable point in the subgroup analysis. Accordingly, the effectiveness of education up to 6 weeks’ follow-up period was significantly more than the other period with low heterogeneity among the included studies. Despite the high rate of heterogeneity, education in Asia was more effective than in other regions.Galipeau et al. conducted a meta-analysis of 9 randomized control trials and quasi-experimental studies to evaluate the effectiveness of all types of prenatal interventions either educational, support, or psychosocial on breastfeeding self‐efficacy up to 4–6 weeks. The included studies were published from 2006 to 2016 in two English or French languages. They reported that overall interventions had a positive effect on breastfeeding self‐efficacy compared with usual care. However, the quality of the included study was low, and the heterogeneity was high. According to the subgroup analysis, they reported that interventions based on theory and direct education methods were more effective than the others. Overall, our result was consistent with the results of Galilean’s study in the term of the type and method of education. However, the Galipeau study was not conducting subgroup analysis based on the type of study, and in other subgroups, the sample size was small [56].Also, in 2019, Ghasemi et al. [8] conducted a systematic review of 21 both randomized control trials and quasi-experimental studies to evaluate the effectiveness of the theory-based intervention (educational and noneducational) on self-efficacy of Iranian women. The included articles were conducted on the Iranian population that was published in the Persian and English languages from 2010 to 2019. They were reported that the breastfeeding self-efficacy of mothers in the theory-based intervention group was more than the routine care group regardless of educational and noneducational intervention. Overall, our results were consistent with the results of Ghasemi’s study in terms of theory-based intervention. However, Ghasemi’s study was not doing meta-analysis and included studies were only in the Iranian population.Also, Brockway et al. [13] in August 2016 performed a meta-analysis on 11 studies, both randomized control trials and quasi-experimental studies. Their study examined the effect of all interventions, whether education, support, counseling, or even screening and mechanical interventions on the BSE. In the event that these interventions are not of the same type, this issue has effect on their results. On the other hand, they reported high heterogeneity among included studies that indicated low quality of included studies. Then, a subgroup analysis showed that only education but not support has a positive impact on the BSE. In contrast to our results, they reported only intervention during the postpartum period but not prenatal intervention, improved BSE. It seems that the difference in the number of included studies in the meta-analysis and different inclusion criteria may contribute to this difference. Their study used only results of 3 studies during the postpartum and 2 studies during the prenatal period that were a combination of support and education. While in our study, 29 studies during prenatal and 11 studies during the postpartum period only with the educational intervention were included. However, we observe that education in healthcare centers was more effective than in the hospital settings, while in their results, education only in a combination setting (hospital and community) affected the BSE. Similar to their study, theory-based education was more effective at improving BSE.We observe that theory-based education in comparison with non-theory-based education can more improve mother’s BSE. Therefore, it is better to use theory-based educational intervention for educating these women. These results are consistent with the theory of self-efficacy, which states that modeling with practice is an effective way to increase self-efficacy [4]. Our results are in line with a previous meta-analysis, which is conducted by Chipojola et al. on 23 randomized controlled trial studies in 2019 [57]. This study indicated the overall effectiveness of educational programs based on theory (the theory of breastfeeding self-efficacy or theory of planned behavior) on the breastfeeding outcomes, and BSE. A high heterogeneity was reported among the included studies that indicated low-quality evidence. The subgroup analysis showed that mothers who received education based on the breastfeeding self-efficacy theory, providing in a hospital setting and developing countries, had a significantly higher score of BSE. Our finding is inconsistent with their results that indicate that education in healthcare centers is more effective than hospital setting. Also, in Guo et al.’s study, there was not seen any significant difference in the term of class format, time of education, and mode of class (face-to face or mobile education) on the BSE. It seems that the differences in inclusion criteria (only theory-based education) and number of included studies are caused by these differences. Another meta-analysis indicated a higher rate of exclusive breastfeeding among mothers who underwent interventions based on the theory of planned behavior [58]. Based on this theory, breastfeeding behaviors are influenced by attitudes, subjective norms, and perceived behavioral control [58]. During these sessions, mothers were taught the importance of breastfeeding and to create a positive attitude with invited influential people, as well as improved their perception of breastfeeding support [58].One of the important findings of this study was that the effect of education on the BSE was significantly greater in Asian countries than in other countries. Therefore, it is important to pay attention to breastfeeding values in each country. Factors such as religion, tradition, culture, beliefs, and customs can affect breastfeeding self-efficacy.Moreover, we observe that the most effective education on BSE was in the first week after discharge. This relationship was seen even up to the 24th week of childbirth. Therefore, it is important to continue education to increase women’s BSE.


### 4.1. Strengths and Limitations

One main strength of the current systematic review was that a large number of electronic databases, as well as hand-search, were comprehensively explored to yield maximum relevant articles on this field. However, the quality assessment of methodology and data extraction were done by multiple reviewers. Also, the subgroup analysis was performed based on several factors that previous studies did not consider them. Furthermore, we excluded quasi-experimental studies, and analysis was done only on RCTs; therefore, the best quality of evidence was available.Despite the study strengths, the results have inherent limitations. In the first place, significant heterogeneity was seen among the included studies. Even after sensitive analysis, the level of heterogeneity was high; therefore, the quality of evidence is low. Although we attempted to make the included studies be like regarding the methodology (only RCTs) and type of intervention (only education), it is not fully achieved even under ideal conditions. Furthermore, regarding the inherent of this study, publication bias is inevitable due to some nonsignificant results that might not have been published. However, included articles that were published only in English and Persian may limit the generalizability to other populations, and this might cause selection bias.


## 4.1. Strengths and Limitations

One main strength of the current systematic review was that a large number of electronic databases, as well as hand-search, were comprehensively explored to yield maximum relevant articles on this field. However, the quality assessment of methodology and data extraction were done by multiple reviewers. Also, the subgroup analysis was performed based on several factors that previous studies did not consider them. Furthermore, we excluded quasi-experimental studies, and analysis was done only on RCTs; therefore, the best quality of evidence was available.Despite the study strengths, the results have inherent limitations. In the first place, significant heterogeneity was seen among the included studies. Even after sensitive analysis, the level of heterogeneity was high; therefore, the quality of evidence is low. Although we attempted to make the included studies be like regarding the methodology (only RCTs) and type of intervention (only education), it is not fully achieved even under ideal conditions. Furthermore, regarding the inherent of this study, publication bias is inevitable due to some nonsignificant results that might not have been published. However, included articles that were published only in English and Persian may limit the generalizability to other populations, and this might cause selection bias.


## 5. Conclusion

Breastfeeding education is considered an influential factor in the improvement of BSE. It is recommended that these interventions are better based on the theory, in healthcare setting, a group class format, during pregnancy, with direct method format, and continued to the first week of postpartum. Considering these issues in designing, an educational intervention provides an important opportunity for health professionals to increase mothers’ confidence for breastfeeding when they encounter breastfeeding problems.



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