Table 3.

Representative quotes from in-depth interviews and focus group discussions (Healthcare professionals, pregnant women, and mothers of children under 18 months).

Healthcare professionals (HCP)
HCP' perception, beliefs and knowledge about mothers' infant feeding intentions and breastfeeding
Infant feeding practices	“...No all women want to BF: 50% of women plan to BF...” (In-Depth-Interview- Nurse, Public hospital).
Knowledge about BF	[Poor knowledge] “...Three months, for most of them. If we're lucky, it's 6 months. But since we see all kinds of people, some of them say they've been doing this for a year and a half, and we tell them to stop. That's something else altogether [...] By then, their milk has less nutrients than “agua de horchata” (rice milk) [...] It depends on what the mother eats and the time she has for it. If you have all the time in the world to breastfeed, awesome, but if not... And sometimes their babies already have grown teeth…Stop!...” (In-Depth-Interview- Obstetrician/gynecologist, Private healthcare facility).
Perception of mother' decisions about infant feeding practices
Perception on mothers	[Additional support] “...No, [mothers don't need additional BF support] because once the mothers are discharged, the pediatricians keep a close eye on them, in every sense of the word. Vaccination, growth, development, feeding… everything. And once more, since mothers are financially able, if they have any questions they call the pediatrician and bring the babies in for an appointment…” (In-Depth-Interview- Neonatal nurse, Private hospital). [Influencers] “...Those who influence the most, I think it is everyone, both medical staff and relatives [...] It is positive. It is positive, but what I have seen is that women, for example, especially young women, get impatient and no longer want to continue breastfeeding, oftentimes because they work. Even if you explain them everything they can do to save the milk in the freezer, the easiest thing is to quit…” (In-Depth-Interview- Physician, Public Hospital). [Reasons to use formula] “... Convenience [...] Well, because they work, because they don't want to... Due to aesthetic reasons, they don't want to look flaccid, because they're lazy and want to sleep more, because they want other people to help feed them, such as their husband, or their mother, their mother-in-law, someone else who's helping out, and they want to sleep, they want to go out and they can't breastfeed comfortably in the street, so all of this can be summarized as convenience…” (In-Depth-Interview- Obstetrician-Gynecologist, Private hospital). [Work as an influencing factor] “… And currently, the main reason why they don't breastfeed is because the woman has to work. So they're away from home for 6, 8 hours, and that's why they can't breastfeed exclusively…” (In-Depth-Interview- Pediatrician, Public hospital).
Beliefs, knowledge, and perceptions about CMF, including specialized formulas	[Use of formulas from stages 2 and 3] “... Most of them do need it. And most mothers do use them…” (In-Depth-Interview- Neonatal nurse, Private hospital). [FUFs and GUMs benefits] “... About starter formulas, well, I think breastfeeding is ideal at first. After they turn 6 months old, they're starting to eat other foods, and the weaning period begins. If they want to stop breastfeeding, I'm obviously not against it and I think they can use formula. They're enriched with Omega-3, DHA, and all of these things that have been proven to be useful in terms of children's neuro-development... And follow-up formulas, from 1 year on, are obviously more enriched with calcium, they even have a better taste, and have everything they need for children to accept them. When they're small, they can't tell you what they like and what they don't, but when they're older, they just leave the baby bottle there if they don't like it [...] Yes, of course [babies need stage 2 and 3 formulas] [...] Yes, I would recommend stages 2 and 3…“ (In-Depth-Interview- Gynecologist, Private hospital). [CMF benefits] “... Um… well, in terms of milk development… well, for babies with special needs, like anti-reflux milks or comfort milks, but those are for—well, maybe they can't tolerate the milk's protein, in some cases…” (In-Depth-Interview- Nurse, Private hospital).
	[CMF benefits] “...Well, that'd be the addition of some components, for example, all of them have iron supplements nowadays, DHA, and there's the ones that are hydrolyzed... There's a formula for all types of intolerance, if I had to recommend a formula, it'd be for those who are intolerant, so, besides convenience, the second reason why they stop breastfeeding is because the babies are intolerant [...] As a result of our current needs. In the past, and I'm talking about when I was young, 40 years ago, we obviously didn't have such advanced formulas. There was the classic one, NAN, and maybe one and two more, and that was it. But nowadays, no matter where you look, you can see more than 20, there's an extensive variety, there's some with more iron, with less iron, Comfort, the ones with Soy, hydrolyzed ones, there's a vast number of them, and they're all in the market because they have certain benefits for the babies. And nowadays, babies are intolerant and have allergies to everything, so the market had to develop formulas that respond to these needs. That's the advantage formulas have nowadays…” (In-Depth-Interview- Gynecologist, Private hospital).
Contact of CMF companies and awareness of conflict of interest	[CMF companies contact] “… And actually a while back I worked at private hospitals and they still do that, “here's your ration of tubs, here's your liquid milk”… it's almost always liquid, then some in powder, and all the usual gifts… baby bags, mugs, photo albums and things like that. Luckily it's not like that in the public sector, so it's good for me, for the babies, and for the moms..” (In-Depth-Interview- Nurse, public hospital). [CMFs companies sponsorship] “… Well, everything's valid, depending on the intention. And their intention is always to sell. So, if they offer you money and ask you to focus on certain aspects and help them promote their products... Well, they're setting your path for you, and you have to decide if you want to follow it or not. But as a pediatrician, you know what you can recommend and what you can't. For example, talking about Nestlé... Who's going to prescribe Gerber? I mean. But their formulas are useful, of course they are [LAUGHS]. And you'll be helping nourish that baby, you'll help them gain weight, have less reflux, not have spots on their skin due to dermatitis…” (In-Depth-Interview- Pediatrician, Public hospital). [CMF companies sponsorship] “… Well, I think it's okay as long as it's a 100% scientific event, so that science can be advanced, I think that's correct...” (In-Depth-Interview- Pediatrician, Private hospital). [CMFs companies sponsorship] “... Everything meant for research and nutrition is excellent…” (In-Depth-Interview- Physician, Private hospital).
Healthcare facilities environment
Breastfeeding-friendly practices at the health facilities	“... To mothers who– If they have a specific prescription due to which they need to formula feed their baby, we have the ability to write them prescriptions so they can get their formula. But it has to be justified. For us to be able to give them formula, they need to have a concrete prescription, and the mother needs to have tried and prove she's unable to breastfeed– she either needs to have galactosemia or the baby should has an illness and can't drink lactose, and in that case, we have drugs here in the pharmacy– I mean, we have special formulas in the pharmacy, and we give that to them…” (In-Depth-Interview- Pediatrician, Public Hospital).
Pregnant women and mothers (FGs and IDIs)
Pregnant women and mothers' perspective
Infant feeding environments	[Hospital practices- supporting breastfeeding] “... Yes, in my case, when I gave birth, in the hospital, they did not want to feed him, they always said: “Bring the baby to the mother, it does not matter milk is not coming out” that's how I was able to produce milk, at the beginning, I suffered a lot because I stayed at the hospital for 3 days and my baby cried for a whole day because I did not have milk, but even then they said: “It has to come out, drink water” so it was hard. I said, don't you see what is happening? But you end up thanking them, because they push you to breastfeed, so you should not put yourself any barriers of saying: “I can't”, you can, in my case…” (Focus group- Mother of baby from 0 to 6 months, currently formula feeding). [Hospital practices- supporting breastfeeding] “... Because I was working, I was pregnant with twins, only one was able to be born, that is why I had a lot of talks at IMSS (Mexican Social Security), they talked a lot about breastfeeding, all government hospitals are pro-breastfeeding, so, they explained all the benefits of breastfeeding, for the child and for myself, it was a lot, same thing with the nurses there, the doctors, then, my husband went with me to the talks, he was also pro-breastfeeding, and after my baby was born, I looked for a pro-breastfeeding pediatrician and my mom use to tell me “just a little formula” and I told her no, only breastfeeding, so, I actually did not paid attention to my mom and only listened to what I heard at the talks from the WHO, and similar things, it was more input from the hospital…” (Focus group- Mother of baby from 0 to 6 months, Currently formula feeding).
	[Workplace environment] “... Yeah, it was my mom at the beginning. I wasn't producing much milk, so my mom would say: “we will have to use formula,” but my sister said, “drink more water, and that will help you to produce more milk. Massage your breast, and insist on it. Don't give him formula.” That's what I did with my first child; I only breastfed him. With my younger child -the girl- I had to use formula because I had to work. I also decided to extract milk and store it, but sometimes I didn't have the time, or I couldn't obtain enough…” (Focus group- Mother of baby from 0 to 6 months, Predominant BF). [Workplace environment] “I know many women who stop breastfeeding their babies and substitute it with formula because they work, and they have to leave them in the nursery because there is nobody there to help them, so they stop breastfeeding.” (Focus group- Mother of baby from 0 to 6 months, Predominant BF). [Workplace environment] “I breastfed my first child for a year, along with other foods, of course. But with X, I decided I might just breastfeed her until she is 6 months old, because I had to work, but now I'm having second thoughts because she is so little.” (Focus group- Mother of baby from 0 to 6 months, occasionally use formula).
HCP, particularly the pediatrician, referred as “authority “ for infant feeding recommendations	“... I feel safe! They know what they're talking about; they know how to explain the information. Other people explain those topics with scientific terms. Pediatricians explain things in a different way; it is easier to get what they say…“ (In-Depth-Interview- Mother, Formula feeding). “... Only my first baby. We visited the pediatrician because she was constipated and she gave me a white one, it has a bear…” (In-Depth-Interview- Mother, Predominant BF). “... In my case, it is my first daughter, whatever the pediatrician says, I have done everything; I mean, the milk he told me was the first one I gave here…” (Focus group- Mother of baby from 0–6 months, currently formula feeding). “... Online and I also call my pediatrician [...] To be honest I prefer to call the doctor. I try to verify what he tells me…” (In-Depth-Interview- Mother, Predominant BF).