Up to 90% of women experience nipple pain or soreness in the initial stage of breastfeeding, with the pain peaking in the first week, then gradually subsiding1. But what if, after 6 weeks, breastfeeding still hurts? You have been observed by what seems like hundreds of lactation professionals, and everything looks fine: your baby is latching on properly and you don’t have an infection. It simply feels to you like she is just a very ‘enthusiastic’ feeder, demonstrated by her toe-curlingly strong suck. Surely that couldn’t be the problem… could it?
Very little research has investigated the causes of chronic pain during breastfeeding, but one interesting study in this area has found a link between nipple pain and a baby’s ‘intra-oral vacuum’, or suck2. The study looked at two groups of women: 30 mothers who were experiencing persistent, unexplained nipple pain (without injury), despite help from lactation specialists; and a control group of 30 mothers with no problems breastfeeding. The vacuum produced by each baby whilst on the breast was measured using a small tube taped to the nipple and attached to a pressure sensor. The amount of milk the babies consumed was also measured, by weighing the babies before and after the feed.
The results were startling. The babies of the mothers who experienced pain when feeding exerted a vacuum when they were ‘actively’ sucking (taking in milk) that was more than 50% higher than the babies in the control group. In between these periods, when they were resting, the vacuum produced by the babies in the pain group was more than twice as high. Unfortunately, a stronger suck did not translate into more milk: babies in the pain group consumed on average 42% less milk, despite feeding for a similar length of time.
The cause of the lower milk intake wasn’t clear. There is a possibility that it was due to chance, or the experimental set-up, although the amount consumed in the control group babies matched that recorded in previous research, making this less likely. As pain can interfere with the let-down reflex, it’s possible that the simple fact that it hurt was enough to stop the milk from flowing properly3. This may in turn have affected milk production, as the amount of milk a baby consumes determines the rate at which it is produced4. It is important to point out, however, that all the babies in the study were gaining weight sufficiently, so the lower milk consumption documented in this single feed did not appear to translate into a more general nutrition problem.
The reason for the higher vacuum is also elusive. It may in some way be the effect rather than the cause of the restriction in milk flow, although this is purely speculative, and how and why this would happen isn’t clear. It’s also possible that the babies in the study may have been experiencing some other feeding difficulty that they compensated for with a stronger suck, although this had not been identified by any of the health professionals who had come into contact with them.
The study data indicate quite clearly that the women suffering from persistent, unexplained nipple pain had babies who exerted a significantly higher intra-oral vacuum on the breast when feeding. Although the data can’t prove the stronger suck caused the pain, it’s likely the two are related. Could this be the reason why for some women, breastfeeding never really seems to become comfortable? If you’re on the receiving end of high suction, then it’s easy to see how you could feel ambivalent about these results. On the one hand, it may be a relief to know that breastfeeding can be painful as a result of the way that your baby suckles, and not because of something that you are doing wrong. On the other hand, the prognosis may be a little disheartening, as it isn’t immediately clear how you solve a problem like this.
At present, such a diagnosis is unlikely, as intra-oral vacuum is rarely tested. The results of this study, however, suggest that in situations where chronic nipple pain has no obvious cause, that it probably should be (the authors certainly think so). Discomfort when breastfeeding is a difficult and stressful situation to deal with, and only with more research in this area can a cause (and hopefully a treatment) be identified. In the meantime, it seems that affected mothers need to carry on gritting their teeth, and perhaps reach for the pain killers…
The Truth About Breastfeeding 
October 22, 2009 at 11:12 pm
There’s one possible explanation for the association between strength of suck, lower milk extraction and mother’s pain that you don’t mention…
Babies breastfeed primarily by thrusting their tongue up against the reservoir of milk behind the areola and squeezing the breast against the roof of their mouths to produce the effect we can mimic ourselves when expressing by hand. This is completely different to the ‘suck’ of a breastpump – or of a baby who has too little breast in his mouth so that he is in fact crushing the nipple against the roof of the mouth instead (signs to look out for are nipple trauma of any kind or pencil-shaped nipples at the end of a feed or sucked in rather than rounded cheeks while feeding). Nipple feeding is very painful and not very effective, precisely because the baby is sucking not pushing the milk out – hence the double whammy of an unsatisfied baby and a mother dreading the start of the next feed.
If this is happening, I’d recommend the mother asks a breastfeeding counsellor how to encourage the baby to open its mouth wider and gets help with positioning the baby to improve the chances of a better latch. Alternatively, self-help by viewing Dr Jack Newman’s ‘how to’ videos.
October 23, 2009 at 7:55 am
Hi Emily – that’s absolutely true, and I agree it probably would have been sensible to mention it! The reason I didn’t talk about it here is that it didn’t apply to any of the women in this study. They had all been extensively checked by lactation consultants and their baby’s attachment appeared to be absolutely fine. I think fortunately this problem only affects a small proportion of mothers – many women who find feeding painful can resolve the issue by making sure their baby is latching on correctly, as you suggest. Thanks for pointing that out – I obviously didn’t make it clear!
March 19, 2010 at 11:53 am
hi there, the article about “strong suck” really helped me to understand what is happening while breastfeeding my baby. In books on breastfeeding they write “use your little finger” to open the vacuum before detaching the baby from your breast. To loosen the jaw of my baby I actually need two thumbs and a lot of force. I always wonder whether one day I will break the baby`s jaw during this bilateral struggle. My breast do hurt terribly when breast feeding but there are no whatsoever signs of wounds or infections and the attachment of the baby has been checked on various occasions by a lactation specialist. I thought: What a wimp I am to think of stoping this horror even though there are no signs of wounds…. Now the big question is, what could be the solution? If the immense vacuum and the terribly strong sucking is one of the less beautiful traits of my baby, then “tough luck”; our days of breastfeeding are numbered. If it is the baby’s reaction on let-down difficulties, we could work on this issue: a peacefull environment and state of mind (which is difficult to achieve once you have started being afraid of the feeding sessions) and probably some more little things the midwife could suggest to enhance the let-down reflex…
December 22, 2011 at 3:36 am
Omg I am SO relieved to have found this post!!! After years of searching for answers to my breastfeeding issues, this could be the cause? With both my children, I had completely normal pregnancies, completely natural out-of-hospital childbirth, and was strongly committed to breastfeeding. But I was horrified when both times breastfeeding was excruciatingly painful from the very first latch. With my first baby, there were apparent problems with the latch and he was sucking (“clicking”) on his tongue. After weeks of trying with two different lactation consultants I was told he was too jaundiced and malnourished to continue trying to breastfeed him and I had to switch to formula.
When I became pregnant less than a year later, I met with three different lactation consultants while pregnant because I didn’t want to repeat what had happened with my first child. All of the consultants were puzzled as to why I thought there might be a problem; turned out my daughter came in the middle of the night and when I went to latch her I was hit with excruciating searing pain. Still determined I met with a lactation consultant the next morning (my latch technique was perfect – not surprising since I had praticed it a zillion times) but she had no other suggestions. For the next 14 months I suffered through breastfeeding/pumping seeing nearly every lactation practice in my city, as well as a variety of specialists from dermatology to the breast center of our research hospital….and each time was given the “party line” that it was either the latch (despite a perfect latch), thrush (despite not having thrush symptoms and both my daughter and myself having negative thrush cultures), or a vascular issue (despite not having any of the signs for this). And then they would say they were stumped; basically what I was told time and again is that chronic breastfeeding pain is a myth and if you feel pain it’s one of these three things or you’re making it up. I was also concerned about the frequency and length of time my second baby was nursing (she was on each breast a good 1/2 hour every two hours, so I basically only got an hour “rest” b/w feedings, but b/c she was growing normally the pediatrician simply dismissed my concerns at every appt.
I called her my “sucky fish” b/c she would even latch through my shirt!
This gives me hope that I may be able to breastfeed subsequent children, or at least know to look out for a strong suction as a potential cause for pain. Thank you! Thank you!!!!! And I think I speak on behalf of all sufferers of chronic breastfeeding pain when I say “IT’S NOT THE F$&@ING LATCH!!!!!!!” (do we need to print it on our shirts?????)
August 14, 2012 at 2:43 pm
Here here! “it’s not the effing latch” indeed! I have a textbook ‘good latch’ with my baby boy and yet my nipples hurt really bad, especially after a good feeding. I am hesitant to spend more money visiting more lactation consultants because I think he just sucks really hard – my baby is on my breast for 20-30 minutes at a time and if I have to break the suction because he fell asleep it is a concerted effort to get my thumb or finger in there to break the latch. Holy moly. I am happy to know others are experiencing the same issue but I also am disappointed because there is no solution and I don’t know how long I can live with this pain. It has been three weeks and everyone tells me the pain should have gone away by now but it certainly hasn’t!
January 8, 2015 at 4:51 pm
I believe this to be true. My 4th baby is a Hoover, lol. Never had nipple pain before, but this time I had significant discomfort. He had a good latch – better than my other babies really. He was a bigger stronger newborn, and he nursed very vigorously. I found nursing more frequently helped it be less painful, since it hurts worse if I am very full. I feed according to my needs rather than waiting for him to demand. At four months I don’t experience much pain. He does this repeated pull off latch back on thing that drives me nuts. When he starts that, I put it away for a few minutes. I also have to unlatch him sometimes when he’s comfort sucking. It just feels like it is pulling too much and becomes painful. I do think relaxing is key to milk supply. I think pain diminishes let down. This time around I feel very sleepy when nursing comfortably. I am not particularly fatigued. I just feel that hormonal wave wash over me. I allow as much night nursing as he wants since I can nurse and sleep. That makes day time easier since he doesn’t need to eat so much.
January 27, 2017 at 10:16 pm
I think tongue & lip ties can affect this as well. My third baby had a posterior tongue tie & upper lip tie that made it hard for him to transfer milk. He was dehydrated & sleepy and not getting enough, but it wasn’t on account of me. I could (& still can) pump 3x what he takes at a time from a bottle! My lactation consultant said that tied babies often had a stronger suck to make up for poor mechanics. He had a visibly good latch & 3 pediatricians all told me he wasn’t tied but it felt wrong (& I knew it from the start, as I nursed my first two). Inside his mouth, however, it was terribly wrong. Just something to consider!