The initial search yielded 633 articles. After removing duplicate records, 378 records were screened through titles and abstracts. Of those, 35 full-text articles were assessed for eligibility based on the inclusion criteria. Those not meeting the criteria were excluded, leaving 15 articles for this review (see Fig. 1 PRISMA flow diagram). The basic characteristics of the articles are shown in Table 2. Regarding the quality of the studies included, two [13,17] were graded as A, and 13 [8, 11, 12, 18,19,20,21,22,23,24,25,26,27,27] were graded as B (refer to Additional file 1).

Fig. 1Table 2 Characteristics of the included articles

Through analysis of the 15 included articles, similar findings were grouped into 12 new categories and finally synthesized into 4 integrated findings (see Fig. 2 Synthesized findings).

Fig. 2Synthesized findings 1: obtaining emotional support

Peer supporters provide emotional support to mothers, aiding them in reducing negative emotions, fostering positive emotions, feeling socially accepted, and gaining confidence in breastfeeding.

Category 1: dissolving negative emotions

Peer support helps dissipate negative emotions mothers experience due to breastfeeding difficulties. The emotional support provided by peers with similar experiences allows mothers to feel less stress. Peer support also works for relieving mothers’ depression.

My failures in breastfeeding made me feel very frustrated and I had postpartum depression at that time, so I kept crying when [the volunteers] came to my home the first two times. They gave me emotional support [8].

I was so stressed because I couldn’t express and don’t know how to express.. and she helped me and to relax me.. [18].

Moreover, peer supporters helped mothers cope with the pain of grief.

She would phone me to make sure that everything was all right and I was not in any pain or anything and if I was worried about anything she would come and see me to check it.. because I was worried about a lot, so she came out a lot to see me. [25].

Category 2: developing positive emotions

Peer support helps the mother keep calm and relaxed facing breastfeeding challenges.

She did a really useful thing actually, which was we did a map of people in my life that I could ask any help for feeding advice and things like that.. and just it just made me rethink and evaluate how much I appreciate having some family closer by. [12].

I was free with her because she’s a mother like me.” “.. The peer counsellor taught me during pregnancy and she came back after delivery when my breasts were very full, painful, and swollen, and then she helped me to express some breast milk and I felt relieved. [26].

Peers share their experiences, empathy, and encouragement enhancing the mother's sense of being understood and having positive feelings towards breastfeeding.

It’s just nice to speak to other women, and I’ve always felt more positive towards the feeding after going to the group. [21].

Category 3: gaining a sense of social connection

Peer supporters are always friendly and warm. They share their personal experiences and emotions with each other, which draws an emotional connection between them. This closeness gives the mother a sense of social acceptance.

I think it was to meet other mums really and.. have a bit of one-to-one contact with other people. [13].

I think just having that additional person to talk to makes you feel less alone.. so it puts you at ease really about how you can actually do it. I think that’s essentially what you want, you want someone to have the same experience as you, you want someone to be like no it’s fine, you are okay. [12].

Category 4: increasing self-efficacy

Peer supporters acknowledge and praise mothers for breastfeeding, which leads to positive feedback.

The counselor’s advice allowed me to be sure about my breastfeeding decision [23].

I always felt more positive about breastfeeding after attending the group. [22].

Mothers receive a self-efficacy boost with the help of their peers.

She [Peer supporter] gave me the confidence.. she passed me on an article, and I’d read that and we worked out things together... [13].

.. For me it was a really positive experience.. those calls and contacts through my first few months.. really gave me a lot of confidence to.. keep going.. [18].

Peer supporters share solutions for breastfeeding problems, and their experiences help mothers to believe in their ability to overcome difficulties and breastfeed successfully.

Very helpful to answer questions the midwives did not have time to go into; this makes a real difference in terms of motivation to continue breastfeeding. [24].

Synthesized findings 2: acquiring knowledge and skills

Peer supporters provide mothers with breastfeeding knowledge and skills that are tailored to their needs and practical.

Category 5: support that meets the needs

Peer supporters provide mothers with breastfeeding knowledge tailored to their needs.

Helped with my breastfeeding education.. that I needed. [23].

That’s what I need to know. Is it normal what he’s doing. I think if I’d found online groups and things earlier than I had, we might not have had so many tears in the first few weeks [22].

Peer supporters always know the effective way for mothers to be able to master breastfeeding knowledge and skills.

You could ask her questions and she’d explain them in a fashion that you could understand without being too medical.. and you could talk to her. [25].

.. I could understand what she taught me.. [26].

Category 6: practical breastfeeding knowledge and skills

The advice and approaches offered by the peers were more practical because they had the advantage of having similar experiences.

I feel very strongly that this useful and practical advice given in the comfort of your own home environment in those very early days was an invaluable support. I can only believe that if more women were given this support there would be much more tendency to breastfeed [24].

It’s like you could go to your GP [General practitioner] and say I’ve got a screaming baby but actually they’re a male GP and they don’t really know. It’s not quite the same. It’s not that I don’t trust the doctor but you have a bit more faith in someone who’s been there, someone who’s been in the situation and can sympathise and say yeah, it’s not easy to breastfeed [22].

Peer supporters help mothers overcome feeding dilemmas with tips and techniques, and their guidance is hands-on.

.. The peer counsellor showed me how to put my baby on my breast properly and since it was the first experience for me, it was useful [26].

I have heard from the girls’ good tips, which I found work. It wasn’t just one tip, they gave me a range of different tips for maybe over one problem [27].

... I had some lumps in my breasts…and they were really, really sore.. um and I had an idea that they were.. some sort of blockage.. she did offer some very good advice for getting in the shower and.. So it never progressed any further than that... [18].

Synthesized findings 3: expectations for breastfeeding peer support

Mothers expect reliable breastfeeding support through friendly interactions with peer supporters. There are variations in their preference for peer support.

Category 7: need for more reliable information

Peer supporters generally do not have a medical background, so the information provided by them is not always perceived by mothers as completely reliable.

It is about your personal experience, just talking to other people in the same group.. There is no reliable information there. [13].

In particular, it was considered difficult to effectively identify information on digital platforms.

I have lingering doubts in my mind, especially about issues that I am concerned about, and I always think about the accuracy of some information [obtained on the internet]. [21].

Category 8: personalized peer support approach

Mothers had varied expectations for peer support, with some preferring digital technology, including phone calls, text messages, and social service platforms. Many mothers said they liked texting for peer support and communication..

... Text message was better because at that point I was always feeding him, so it was quite difficult to get the phone, so with the text it was more easy because I just answered when I could and she the same. [12].

Some mothers used to obtain peer support through online social media. Social media provides quicker and more timely access to information than face-to-face communication.

... Such as FaceTime, which is convenient for volunteers because they don’t have to do home visits, and also good for mothers; otherwise, the mothers have to arrange a time to meet [volunteers], which will be stressful. [8].

When I had nipple thrush, I definitely searched the internet for nipple thrush and read what people said about help for that. [13].

Facebook helps find the content of interest and offers help in a tailored way. [19].

Peer support in the form of groups can help mothers receive more rich input from a variety of different people.

People have different requests, but other people have given answers.. which is truly niche. [13].

I think it is great to have professionals involved as well. [20].

Because of different cultural backgrounds, mothers need support from specific breastfeeding peers with similar experiences, and they need support from dedicated media groups even more..

Well, we have many experiences that are unique to Black women that we cannot explain to other people, so an inclusive group is definitely needed. [17].

However, some mothers felt that it was still face-to-face peer support that allowed them to receive more beneficial help.

She calls you, but that is not enough to benefit from her. It is no better than someone who spends an hour and a half visiting you and teaching you baby care. [22].

Regarding the timing of peer support, some mothers wanted help early to receive longer and more frequent interactions to help them cope with any problems that might arise.

If I were well prepared before birth, it would be much better than preparing after birth. [8].

In contrast, some mothers preferred later.

I did not really want to acknowledge until the 20-week scan.. 12-weeks.. I do not think I was even thinking about post-birth. [12].

Category 9: friendlier interactions

Mothers felt that social platforms, due to their anonymity or nonface-to-face nature, led to more direct or carefree expressions from those online, leading to some negative emotional experiences for mothers. They would like to see friendlier discussions on social platforms.

I think sometimes conversations can get a little heated. And um, I think they’re a little harsh at times for people who may be, are not using the search feature or asking a very commonly, a common question and people just kind a pounce on them. So, I think people may get discouraged. [17].

You would want to get honest opinions from people, not criticism or something like that. [13].

I just got into a heated argument with someone I have never met before, and I do not think that would happen in real life. [22].

Synthesized findings 4: feeding perception and behavior change

Peer support has a significant impact on mothers’ perceptions and behaviors towards breastfeeding. It encourages them to accept and adhere to breastfeeding, and even inspires them to become breastfeeding peer supporters themselves.

Category 10: acceptance and support of breastfeeding

Peer support helps mothers accept breastfeeding by addressing misconceptions about breastfeeding.

... It’s sort of give me confidence to not really care about the rest of societies [society’s] opinions as long as I am happy with my own mothering and parenting. [22].

Breastfeeding images allow mothers to accept breastfeeding in public.

I feel the images are amazing. They’re so uplifting. There was one, um, that empowered me so much the other day. It was a woman breastfeeding her daughter at a restaurant, and today, I thought about that, and I’ve been thinking about it for days, and I went out today, and I did it... [17].

The support the mother gained from the peers reinforces her to continue breastfeeding.

Well originally before I came across the Breastfeeding in Northern Ireland page I think originally my goal was to get to the minimum six-month period and now having educated myself my goal is probably to get to either the age of two or a natural weaning point or when I get pregnant again and I can’t... [20]

If I didn’t have the peer supporter to talk to about things I would be more likely to give up [24].

Mothers who received peer support were more likely to be breastfeeding advocates.

I think also it’s nice to be able to give support, because in these groups you’ve got people who have just had babies and it’s nice to be able to say actually I’ve been there now. So, where people have answered my questions, I can hopefully answer theirs [22].

Category 11: extended breastfeeding duration

Peer support increases mothers’ confidence to achieve their goal of breastfeeding longer.

Without this study I could have stopped breastfeeding from the first month.. Without the help of the peer support and consultant [11].

It’s been great to see that there’s women that do it for 12 months, two years, and so that six-month goal doesn’t seem so unachievable. It kind of almost makes you feel– it motivates you to keep going. [19].

Category 12: desire to be a peer supporter and give back to others

As mothers became more familiar with breastfeeding with the help of peer support, they became very willing to offer help to others.

Because it’s important to see women that look like us doing this stuff. Marrying that up with what I learned in the class that I took for the CLC [Certified Lactation Consultant]. So, yeah, this [breastfeeding] would have been a done deal, and I wouldn’t be this advocate. I wouldn’t be posting breastfeeding on my Facebook page, I wouldn’t be going to support groups if it wasn’t for the group. [17].

Providing support to other mothers not only gave them a sense of accomplishment but also enhanced their own breastfeeding experience.

... My need to empower other women with up to date, correct information is being met.. making new friends hopefully, and.. feeling the breastfeeding love.. [13].