How much will my breasts enlarge?

[L0ngg0ne]

I’m 9 weeks pregnant and have always had small breasts (about an A-B cup). I plan to breastfeed, and although my breasts have enlarged a little during the pregnancy, I do look at them wondering how much milk they’ll really be able to hold? Are they likely to enlarge further to facilitate nursing, or might there be a chance that I’ll struggle to produce milk? Perhaps the size of my breasts are absolutely fine, I just ask this as it’s occurred to me that I’ve only ever seen women with breasts larger than mine nursing. My breasts aren’t that small, at the moment - I’d say about a decent B cup.

I guess my questions are the following:
How large must breasts be to produce milk and facilitate breastfeeding? If my breasts are currently ‘too small’ to produce milk and facilitate breastfeeding, are they likely to grow to a size that allows them to do so during the remainder of my pregnancy?

I know these are strange questions, I’m just a little concerned I guess.

Thank you for your thoughts.

Breast size has absolutely nothing to do with milk production so you don't need to worry. Everyone is different - some people increase their size by several cups, some don't change at all. It makes absolutely no difference.

As mentioned breast size has absolutely nothing to do with milk production, your breasts don't really store lots of milk like a lake, they are more like a river with milk constantly being created flowing endlessly.

Impossible to tell how big they'll get, mine have never changed cup size through two pregnancies and feeding my son for 2 years and preparing for dc2 now. My band size goes up as my ribs expand in pregnancy but that's it.

Flat as a pancake and still breastfeeding 14 month old. Had plenty of milk and it went really well. I had the same concern deep down but it proved completely unfounded. Good luck!

I've bf both my DCs and never had an issue with supply although I had been worried about it before DC1 was born due to bust size. But as mentioned above, size doesn't effect milk.
Personally in terms of how much mine grew, I started as a B and went up to a DD whilst pg and bf. I stopped feeding DC2 6 months ago and they seem to have settled back at a C.

Breast size is basically determined by how much fat you carry there, while milk production is determined by mammary glands and milk ducts, which take up very little space. You don't "store" milk in the breast between feeds, it's made on demand, so size genuinely doesn't matter.

I went up about a cup size.

I started out with A/B cup boobs (wore a B but they always gaped). I bf ds for a year and am now bf dd. He was on the 91st percentile for weight and she's on the 98th, so they were/are great big chubby babies and I've got milk galore! My old B cups are now snug/full and I have cleavage for the first time ever, but Cs gape.

One thing that did change with regards to my bra size was my back measurement as my ribs expanded to accommodate my big 3rd trimester bump with dc1. My rib cage has never quite gone back to being as narrow as it was pre dc.

I went from a B to E with my first, down to a D when I stopped breastfeeding... upto an E when I gave birth again, down to a DD.... currently an E when pregnant again

B cup here and went up to a full B/C in pregnancy, which I was quite disappointed about as I was expecting to finally have bigger boobs. No problem breastfeeding at all, still going strong at 9 months. Only thing I found annoying is that all shops assume breastfeeding women have large boobs. I couldn't find a decent nursing bra that would fit me band size. Most start at a 34C so I have just ended up wearing a sports bra type one which don't exactly look great!

Mind went up one cup size during pregnancy and up another cup size over night when my milk came in (ouch) then dropped one cup size four months later. Breastfeeding isn't about size. The milk should just come in the quantities that you need it as opposed to filling up your breast then stopping (they won't stop producing milk until you've been engorged and leaking for days).

I went from a C to a G when my milk came in, they have settled at a DD/E now DD is 13 months. Size of breast means nothing in terms of milk production, so don't worry about that, everyone's body is different and will change in different ways during pregnancy but the majority of women will be able to breastfeed with the right support.

I was a size B too. Once my milk came in they swelled 4 cup sizes to an F! Don't worry your body adjusts it's so clever :-)

After breastfeeding they reduced right back down to an A/B again (just not as firm!)

I was a 32dd, currently 28 weeks pregnant and they are a gg. The idea that they can get bigger is giving me the fear...but basically like everyone’s said, size nothing to do with milk production. Am slightly concerned if they get much bigger how tiny baby will latch (first pregnancy obviously) but assume women of all sizes manage to feed so it can’t be that much of a problem!

My breasts didn't grow at all during pregnancy or breastfeeding other than the initial period of milk coming in and fluctuation throughout the day (in the early weeks).

As PP have said though the size has nothing to do with ability to BF. Only a very very small amount of women can't breastfeed.

Went from 30FF to 32J when I was pregnant with my son (6 cup size increase), stayed at a 32H while I was breastfeeding him, I'm now 24 weeks with #2 and I'm around a 32HH so very little change this tim mercifully!

Both pregnancies mine haven't increased in size from 34A. With DS I had an initial increase once milk came in to a B cup, but settled back down again. Breastfed him exclusively till 6 months and carried on till he self-weaned at 31 months. DD due in 3 weeks and imagining similar.

Remember at breastfeeding workshop before DS midwife told us about a lady who wasn't even a AA cup and breastfed all 3 of her children without probs.

My breasts didn't get any bigger at all while pregnant, sooooo disappointed as they stayed a B throughout (I'm fat everywhere else). I did go up from a 36 to a 40 though. Boobs got bigger once milk came in but it was temporary. Never had a problem BF but did have to feed often and never got on with expressing. Just didn't seem to be any spare for that. No idea if this is related to breast size.

A colleague of mine was too small for nursing bras but BF two children no problem at all.

I was a 34A before I became pregnant, went up to a 34C while pregnant then up to a 34D when I started breastfeeding. I am still breastfeeding 17 month old DS but my breasts have started to shrink back down again - my D cups are starting to get a little loose. I think that the most of the size change was down to fat - I definitely gained a bit too much weight, and it is only now that it has started to come off that my breasts have shrunk again.

My sister is also an A cup, but her boobs never changed size - however, she also breastfed very successfully. As PP have said, there is no relationship between breast size and milk production.

I have the same issue as Boodles re sizing assumptions. My band size has gone up with a much smaller cup increase (36wks). I’m now a 38A and nowhere makes nursing bras in that size that I can find.

I’m counting on my ribs going back together so I can get something to fit properly after the birth. So annoying!

Nothing to stress about, it's definitely not the size that determines milk production potential! I'm about the same as you and weirdly mine didn't get bigger, but I had enough milk for my little one no problem. Sometimes I could feel the tingly sensation under my arms so I knew my milk glands stretched far!

I went from an AA to an A
I managed to breastfeed. DD wasn't keen to latch on at first, but once we had both mastered the technique I made plenty of milk for her, despite remaining an A cup all through breastfeeding (actually probably a B from the MN intervention). I had optimistically bought some C cup nursing bras, but had to return them unused. In the end I didn't bother at all with a bra while breastfeeding (I never had any leakage).

MIL always used to say the leanest cows make the best milk - probably to make me feel better about my lack of cup growth.

To those saying that milk is not stored in breasts but instead produced on demand whilst feeding - why then do breasts get engorged if you do not feed for several hours?

Having exclusively pumped for several months I can say with confidence that my breasts produce milk at a constant rate (about 50ml/hr between them) and store it until extracted or until full (which happens when there if about 150ml in each breast in my case). If I pump before they have filled up, there is simply less in there!

Supply and demand is a much slower process eg if more milk is needed over several days the rate of production increases (eg from 50ml/hr to 55) but I am not going to suddenly make 200ml in an hour just because I keep pumping!

All that said I believe it is correct that the size of your breast does not directly reflect the milk storage capacity as most of the breast is fat rather than milk ducts.

It's a simplification of the process. Milk isn't only produced while feeding, it's also produced all the time, as you've found, particularly in the early weeks/months. If the milk isn't being pumped/drunk then it doesn't have anywhere to go so it does then begin to fill up the milk ducts and so on, leading to feelings of engorgement and/or leaking. One analogy sometimes used to explain this is that breasts are sort of like a reservoir. And yes, once the breasts are full of milk this does send the signal back to the body to reduce supply and this happens over several days.

There is some research but I believe it's preliminary about women having different storage capacities for this in-between-feed produced milk, and the thinking is that this may be why some women's breastfed babies go longer between feeds whereas others want to feed much more frequently.

150ml is a lot to get from each breast per pumping session, even when you exclusively pump, I would say this is unusual and you may have a high storage capacity or high supply compared to most women.

They do say that a baby is more efficient than the pump and can usually get more out even when your pumping output is nil. But certainly when you're "due" a feed and your breasts are fuller the milk will come out much faster, when your breasts are empty, despite the fact there is still milk there, the baby has to work much harder for it.

Im an A my breasts didnt chsnge at all in either pregnancies and though i did produce milk i had no physical changes then either definitely no emgorgement. I tried to bf both times abd it didnt work out but i was told it was nothing to do with size

I should add most women will find that their supply changes or regulates at around the 3-4 month mark. This can be a sudden or gradual change. She will find that she no longer routinely gets as engorged between feeds, only if it has been much longer than usual, and many women find that they stop leaking as much. If she is pumping she will often find that her output drops but quite a large amount (I believe this works differently when exclusively pumping and output can stay high).

This can be quite alarming if you've been under the illusion that storage capacity is related to supply. It's thought to be something to do with a shift from hormone driven supply to more demand driven supply, because when you first give birth your body doesn't know how many babies you've had, plus newborns are not always the best at feeding/stimulating supply very well, so you produce loads extra just in case.

For women with oversupply this shift tends to happen later, around the 6-9 month point.

I believe it's ongoing as well - certainly even though I experienced this shift at about 3 months I could express small amounts until about 9-10 months, by which point I couldn't get anything out yet DS was still getting plenty of milk himself. At this point towards a year+, the breasts can also handle much longer absences without becoming engorged. And if you stop breastfeeding later than about 18 months or so many women find that they are still producing milk weeks after stopping.

I think it's quite fascinating - it seems to go from a state where supply is quite fragile in the beginning but is boosted by hormones, perhaps to make it go the distance - to a state where supply is much more robust but the "backup" of the extra stored milk just isn't there.