Nipple shields and milk yields: an update

In a previous post I questioned the received wisdom that using nipple shields will have a negative impact on your ability to nurse your baby (see nipple shields: always a bad thing?). The post challenged one of the main criticisms made of shields — that they slow milk transfer and may therefore mean your baby is inadequately nourished — on the grounds that most of the studies demonstrating this were conducted a long time ago, and more recent research indicates that this problem does not exist for modern shields1.

The researchers who conducted the study in question concluded that nipple shields do not affect the amount of milk babies consumed in a feed by weighing before them before and after they nursed: when a mother was using a shield, the amount by which her baby had increased in weight at the end of the feed was roughly the same as when she was breastfeeding directly. Whilst this result looks positive for nipple shields, ‘test-weighing’ babies in this way is not without its critics, so one could argue that concluding nipple shields have no effect on milk consumption based solely on this evidence is a little premature.

Since writing the post, a follow-up study has been published, this time looking at the relationship between shield use and infant weight gain over a much longer period2. 54 mothers who used a nipple shield provided by a nurse or lactation consultant in the period just after the birth of their babies were recruited for the study, and completed interviews when their babies were 2 weeks, 1 month and 2 months old. Over time, the proportion of mothers using shields diminished (at 2 weeks,  69% of the mothers were still doing it, at 1 month 48%, and at 2 months 33%) and at each stage the responses of women who were still using the shields were compared with those who weren’t.

The main aim of the study was to determine whether nipple shields had a negative impact on weight gain — if babies whose mothers were still using shields grew more slowly than those whose mothers had stopped, then this could be taken as an indication that medium to long term use of shields was causing a real problem. Happily, there was no difference between the groups: whether a mother used a shield made no difference to her baby’s pattern of weight gain.

There were a few complaints about nipple shields: 8 women thought they caused nipple soreness; 2 found them messy; 2 found them inconvenient and 3 had problems with them falling off. In spite of this, 90% of the mothers in the study said that using the shield was a positive experience, and 67% felt it helped prevent them from giving up breastfeeding.

If you are a mother who relies on a nipple shield to breastfeed, these results make reassuring reading. Although shields appeared to cause difficulties for a few women, these were generally minor, and crucially they concerned practical issues, not the health of their babies. As most women felt that shields helped to prolong the period that they were able to breastfeed, this study ultimately supports the view they could be an important intervention for mothers who are having problems, rather than something that will make them worse.

  1. J Obstet Gynecol Neonatal Nurs. 2006 Mar-Apr;35(2):265-72.
  2. J Clin Nurs. 2009 Nov;18(21):2949-55.

Nursing strike: self-weaning or a sore throat?

thermometerSince starting solid food, C had had a remarkably relaxed attitude to breastfeeding: she never gave any indication she actually wanted to do it, but when offered the chance she was always happy to tuck in. This was particularly true when she was ill. Often she would go off solids, but would still be happy to breastfeed frequently, which reassured me she was receiving at least some form of nutrition.

When C was got a particularly nasty cold at around 11 months, I didn’t worry too much about her loss of appetite, assuming that I would be able to top her up with breast milk as usual.  Unfortunately, C had other ideas. After a few tentative sucks, she turned her head and pushed me away with a resounding, ‘no!’ Although part of me was delighted at how well she had articulated her refusal, the rest of me was upset, almost alarmed at the suddenness of it. C had never refused to breastfeed before. Certainly, some days she was keener than others, but this outright rejection was completely new. Although the following morning I managed to feed her again when she was half-asleep, it was the only time she nursed in a 24-hour period.

This pattern repeated itself the following day, leaving me frantic with worry. What had happened to put her off? Was it something I’d done? Was it simply her time to wean? How would I know the difference? Obviously if C genuinely did want to wean, I didn’t want to pressure her to carry on breastfeeding, but as stopping was pretty final, I didn’t want to do it unless I was absolutely sure it was what she wanted.

I was shocked at how C’s nursing strike impacted on me emotionally. I was teary, overwrought and pretty much incapable of thinking about anything else. It seemed important to get it into perspective, however, so I eventually pulled myself together enough to consider the issue rationally. One major clue to the source of refusal was staring me in the face: not only was she shunning breast milk, but she was also refusing bottles, and with the exception of yoghurt, pretty much any food or drink. Whilst this was incredibly worrying in some respects, it did point to the fact that the problem may be less to do with breast milk, and more to do with consumption generally. I then started to think about the nature of her illness, and concluded her symptoms were pretty similar to the ones that I had at the time – a runny nose, cough… and a sore throat. I didn’t know whether C’s throat was also sore of course, but if it were, then it would be a pretty convincing reason for not swallowing unless it was absolutely necessary. The cold I was suffering from had left the roof of my mouth pretty tender too, which, if you think about it, could make breastfeeding particularly unappealing.

I continued to offer C feeds, which she would sleepily accept once a day, and after a week or so she was almost back to her normal routine. I can only assume that the strike occurred because of her illness, and now she was feeling better, she was happy to breastfeed again. Although the incident was traumatic in some ways, it did at least leave me confident that if C goes off breastfeeding because she’s ill, it’s something we can get through, and if she’s stopped because she wants to stop… well, that’s something we can get through too. When the time comes for her to genuinely wean herself, I now think I’ll be able to cope with it a little bit better, and simply be happy that she’s growing up and gaining independence.

Can breast milk cure an eye infection?

eyeOne of the many healing properties attributed to breast milk is the ability to cure eye infections such as ‘pink eye’ — conjunctivitis — or ‘sticky eye’ — a gooey discharge that often accompanies conjunctival inflammation. Conjunctivitis is a common condition that rarely requires treatment, usually clearing up by itself within a week or two. For newborns, however, it can occasionally be quite serious, so ensuring it is properly treated is very important. For everyone else, it can be irritating and unpleasant, so any way of reducing the length of the infection is naturally welcome. Can breast milk really provide any relief?

A study in a hospital in New Delhi, India, examined the effect that routinely applying colostrum to babies’ eyes had on the likelihood of them developing an eye infection1. On one hospital wing, mothers were asked to put a drop of colostrum in their babies’ eyes three times a day; on another wing, mothers were asked not to apply anything. The infection rate was much lower in the babies who received colostrum: only 3 out of 51 babies in this group (6%) developed an infection, compared to 26 out of 72 in the control group (35%).

At first glance, this seems like a convincing result for colostrum, but a closer examination of the figures indicates this isn’t necessarily the case. The normal neonatal eye infection rate recorded at the hospital was just over 5% – roughly the same as the one recorded in the colostrum group. Rather than infection rates going down in the babies who received colostrum, it seems they went up – considerably – in those who didn’t. This may have occurred because the normal practice of wiping eyes with a sterile swab just after birth was abandoned during the study. Fewer babies in the study group may have got infections simply because their eyes were rinsed, not necessarily because it was with colostrum.

There is other evidence that breast milk could help ease the symptoms of conjunctivitis, however: in vitro tests show that colostrum, and to a much lesser extent mature breast milk, can potentially combat some of the bacteria known to cause neonatal eye infections2,3, and another study provides evidence that it does seem to be an effective treatment for eye infections in young babies4. At a hospital in Spain, babies diagnosed with neonatal sticky eye were treated either with antibiotics or breast milk. Babies treated with breast milk generally recovered much faster: 26 out of 45 (57%) of those receiving milk had recovered after 30 days, compared with 3 out of 20 (15%) of those receiving antibiotics. Whilst this does not provide conclusive evidence that breast milk is the optimal treatment for eye infections in newborns, the study’s results were deemed sufficiently encouraging to switch from antibiotic drops to breast milk at the hospital where it took place.

So does this limited evidence that breast milk can treat some neonatal eye infections mean it can be used to treat infections in older children, or even adults? Whether breast milk would have a beneficial effect is not clear: its antibacterial properties mean that it may help to clear up an infection caused by certain types of bacteria, but not necessarily one resulting from an allergy or a virus. Having said this, there is, of course, no harm in trying the breast milk option. If you’re currently nursing, it’s simple and free, and whilst it may not get rid of the symptoms, it almost certainly won’t make them any worse.

  1. J Trop Pediatr. 1982 Feb;28(1):35-7.
  2. J Trop Pediatr. 1996 Dec;42(6):327-9.
  3. J Reprod Immunol. 1998 Jul;38(2):155-67.
  4. J Trop Pediatr. 2007 Feb;53(1):68-9.

Breastfeeding and thrush: preventing reinfection

microwaveA bout of thrush when you are breastfeeding can be problematic in many ways. Not only are candida yeast infections often painful and tricky to diagnose, but they can also be remarkably persistent: antifungal medication may appear to alleviate the problem, but not eradicate it completely, or it may clear up one episode of thrush, only for another to appear a short time later.

One reason for the longevity of nipple thrush is the high potential for re-infection. Medication can keep yeast at bay while you are using it, but as soon you stop you become vulnerable to attack again. The most potent reservoir for candida species that your nipple comes into contact with is your baby’s mouth (even symptom-free babies are often carriers1), so ensuring this is treated with an antifungal at the same time as your nipples is essential for effectively combating thrush. It is not the only place spores can gather, however – hands and other objects can easily become colonized too, and whilst washing something that has only been in contact with candida spores for a short time can usually get rid of them2, certain objects are able to host thrush for quite a long period.

Towels and clothing are among the surfaces that are at high risk of habouring candida. A study looking at the length of time fungal spores could exist on a variety of fabrics used in hospitals found that candida survived for an average of 5 days after inoculation, and lasted longer on synthetic materials (polyethylene, polyurethane, spandex, polyester) than cotton or fabrics that were a mixture of natural and synthetic fibers3. Washing fabric can eradicate thrush, but it may need to be at a high temperature: one experiment found that candida spores could survive the wash at 50 degrees Celsius, but not 704 (although it should be noted that this research was conducted some time ago, and modern detergents may be more effective at lower temperatures).

The use of a pacifier is significantly associated with oral thrush in babies, indicating that dummies or soothers may also provide a friendly environment for candida spores1. A study examining the microorganisms prevalent on the surface of pacifiers showed that this was indeed the case. Like teeth and dentures, pacifiers can develop biofilms that play host to a complex array of microorganisms including numerous bacteria and funghi5. Biofilms are pretty persistent: simply ‘sterilizing’ with boiling water will not remove them5,6. It is not impossible to get rid of them, however, and in fact an effective means of doing this can be found in most domestic kitchens. When candida spores are subjected to microwaves for a sufficient length of time, their cell membranes are irreparably damaged, rendering them ‘inactivated’6. Three minutes immersed in water in a 650W microwave is able to eradicate candida from dentures7, and the chances are this is also an effective way of sterilizing pacifiers.

The best way of treating thrush is to take a sufficient course of antifungal medication, but to prevent it returning it is also a good idea to ensure that anything coming into close contact with nipples or mouths (such as towels or pacifiers) is kept free of rogue candida spores. Whilst washing hands in soapy water will generally decontaminate them, this is not necessarily the case for fabric or pacifiers, which can provide a home to yeast spores for some time, even after they have been superficially cleaned. To get rid of candida for good, there are two options: a hot wash or session in a microwave; or throwing everything out and starting again. Whilst the second option may be tempting, it may also prove rather expensive – fortunately the first option should do the job just as well.

  1. J Oral Pathol Med. 1995 Sep;24(8):361-4.
  2. Eur J Clin Microbiol Infect Dis. 1994 Jul;13(7):590-5.
  3. Clin Microbiol. 2001 Sep;39(9):3360-1.
  4. Br J Vener Dis. 1984 Aug;60(4):277.
  5. Nurs Health Sci. 2006 Dec;8(4):216-23.
  6. Mycoses. 2007 Mar;50(2):140-7.
  7. J Dent. 2009 Sep;37(9):666-72.

Breastfeeding and thrush: what are the treatment options?

medicineThe symptoms associated with thrush (a candida yeast infection) in breastfeeding women vary. Some have red or shiny nipples, fissures or flaking skin, others exhibit no visible signs at all1. There is one symptom, however, that is reported almost universally: pain. It is usually described ‘in the strongest terms, with words such as “agonizing” or “excruciating” often being used’, and can occur throughout a feed and continue for sometime afterwards2. Faced with this level of discomfort, it is not surprising that many mothers diagnosed with thrush feel unable to continue breastfeeding3,4.

This shouldn’t be the case, of course; fungal infections are highly treatable, so contracting one need not automatically spell the end of breastfeeding. Unfortunately, getting medication for this type of thrush isn’t always straightforward, particularly if you are unlucky enough to have an unsympathetic doctor (see breastfeeding and thrush: it’s complicated). Health professionals who are reluctant to diagnose thrush, are naturally hesitant to prescribe for it, so some mothers may be left suffering unnecessarily, or given the wrong medication, such as antibiotics, which may actually make the condition worse2.

An additional problem is that the evidence base for treating breastfeeding yeast infections is sorely lacking. Although there are many antifungal drugs available, there have yet to be any controlled clinical trials examining their effectiveness for treating a candida infection of the breast. The difficulty confirming a diagnosis may be one reason for the lack of trials: milk and skin cultures aren’t always reliable, so it could be difficult to know whether a treatment failed because the drug was ineffective, or because the symptoms weren’t actually caused by candida. Alternatively, it may be because this research simply isn’t viewed as a priority: if an infection is caused by candida, then it should clear up eventually providing enough antifungals are thrown at it5. This ignores the possibility that the unique environment breasts are subject to during nursing may impact on the effectiveness of a treatment, but at present it’s the most ‘scientific’ approach we have.

Case studies and anecdotal information sources (which generally consist of health professionals giving opinions based on their clinical experience) also offer theories about the best way of treating thrush. A traditional medication for nipple thrush recommended on numerous breastfeeding websites (albeit mostly in articles written by the same person) is gentian violet, a purple ointment that can be applied to both nipples and babies’ mouths. Although there are no controlled clinical trials supporting its use for nipple thrush, it is known to be an effective antifungal, and there is anecdotal evidence it can be helpful for breastfeeding women2. Gentian violet does have its drawbacks, however. A minor issue is that it is messy (it is used as a dye); a more serious concern is that it can cause skin irritation6 and may be carcinogenic7, and as such it is not available for this purpose in the UK.

Due to the lack of clinical research in this area, there is no definitive list of drugs that are suitable for treating thrush in breastfeeding women, so theoretically any medication that is antifungal and unlikely to cause problems for a nursing baby could be prescribed. Common topical treatments include miconazole and clotrimazole, which are usually supplied in creams or powders. These are not advised for internal use, so it is generally recommended that they are removed before breastfeeding, although this is due to the ingredients in the base of the medication, rather than the antifungals themselves (both can be used to treat oral thrush if they are supplied in the appropriate preparation). Nystatin can also be applied topically to the nipples and is usually supplied in a formulation that does not need to be washed off. It is often used for treating thrush in babies’ mouths, and as such is often the first medication suggested for treating mothers too5.

Anecdotal evidence suggests that topical treatments aren’t always effective, however, and thrush can be treated more reliably with fluconazole5,8 (a clinical study suggests that this is the case for oral thrush too9.) Unlike creams and ointments that only treat the skin where they are applied, fluconazole has the additional advantage of being taken internally, providing a blanket assault on candida wherever the site of infection.

Although organizations like the Breastfeeding Network and the NHS suggest that fluconazole is a good treatment for mothers who appear to be suffering from persistent thrush, it can pass into milk in small amounts, and is not currently licensed for use when breastfeeding. As it can be safely given to newborns, this is not a great concern. The fact that the breastfeeding box isn’t officially ticked can make doctors cautious, however, leaving some women without potentially important medication. The opinion that fluconazole shouldn’t be given to breastfeeding women unless it is part of a controlled clinical trial can also be found in the scientific literature10, and while this idea is reasonable in theory, until someone actually gets round to running the trial, it isn’t so great for those women experiencing ‘intolerable and incredible pain’ that may be due to thrush11.

At present, there isn’t any concrete evidence that fluconazole (or indeed, any medication) is suitable for treating yeast infections in breastfeeding women, because there haven’t been any controlled clinical trials looking at its use in this situation. Until such trials are conducted, there are a couple of options. One is to deny women antifungal medication on the grounds that there is no proof it works. An alternative – supported by numerous breastfeeding organizations – is to advise women with suspected thrush to take fluconazole orally, to treat nipples topically and ensure their babies’ mouths are treated too, in the hope of alleviating symptoms. Proper research in this area would naturally be a great step forward, but until it occurs (if it ever does), it seems only fair to offer women suffering very painful symptoms at least a chance at respite, particularly if it enables them to continue breastfeeding.

  1. J Hum Lact. 2004 Aug;20(3):288-95.
  2. Aust N Z J Obstet Gynaecol. 1991 Nov;31(4):378-80.
  3. J Obstet Gynecol Neonatal Nurs. 2005 Jan-Feb;34(1):37-45.
  4. Clin Pediatr (Phila). 2001 Sep;40(9):503-6.
  5. J Hum Lact. 1999 Dec;15(4):281-8.
  6. J Hum Lact. 1990 Dec;6(4):178-80.
  7. Fundam Appl Toxicol. 1985 Oct;5(5):902-12.
  8. J Hum Lact. 2002 May;18(2):168-71.
  9. Pediatr Infect Dis J. 2002 Dec;21(12):1165-7.
  10. Breast. 2002 Feb;11(1):88-90
  11. J Hum Lact. 1997 Dec;13(4):307-11.

Hydrogel dressings in the British Journal of Midwifery

nurse-with-clipboardA few weeks ago, I talked about a ‘clinical case study’ posted on a medical supply manufacturer’s website, apparently demonstrating the benefits of using hydrogel dressings when breastfeeding. Unfortunately, the study was poorly designed, and therefore unable to provide support for its considerable claims. It showed, at best, that the dressings did not appear to cause any major problems for a small group of women.

Since then, the dressings have been tested in a larger, controlled study, published in the British Journal of Midwifery1. The article, which describes the dressings as ‘designed to physically protect wounds while maintaining a moist environment,’ concludes that, ‘the dressings can reduce the pain and discomfort associated with nipple excoriation.’ This rhetoric sounds pretty impressive – but does it accurately reflect the strength of the evidence?

On the surface, the study appears to be well designed and reported: 64 mothers were randomly assigned to either the experimental group (wearing dressings between feeds) or the control group (rubbing breast milk on the nipple after a feed), and self-reported pain scores were recorded in interviews 5 times over 14 days. If you read the article carefully, however, a number of inconsistencies become apparent. The abstract and ‘study objectives’ sections say that the aim of the study was to compare the dressings with ‘breastmilk expression and patient education (control group).’ We learn later that in fact both groups received education. The study hypothesis was that, ‘the dressings may reduce nipple pain and excoriation.’ While excoriation (skin wounding/abrasion) is mentioned several times, it was never actually measured – or if it was, the results are not reported.

That the dressings resulted in ‘a considerable reduction in pain’ is highlighted in a special ‘key points’ box. In fact, pain was significantly lower in the dressings group on only one occasion – day 12. The results section states that the average score for the dressings group on this day was 1.3, compared to 2.0 in the control group, and refers you to a graph showing how the scores declined over time. Confusingly, this graph shows the control group score on day 12 not as 2.0, but as 1.4. Clearly, one set of figures is wrong. Given the gradual downward trend of both sets of scores, it would be pretty odd if a pain score went from 1.4 two days previously, to 2.0 (the highest score, recorded at the start of the study), and back down to 1.4 two days later. It seems more plausible that the figures are misreported in the text, and that the statistical tests were in fact conducted with errroneous data. ‘Comfort scores’ are also reported to be consistently lower in the dressings group, although it is not completely clear what these are. They are not mentioned in the method section, and are described in the results section as ‘acceptance of the treatment’ measured using the 1-5 verbal descriptor pain scale. This is the same scale used to measure the other pain score, and how the two actually differ is not explained. Again, the graph and text do not match. The text says that comfort was recorded on days 3, 5, 10 and 12, but the graph also shows data for this measure on days 7 and 14. Interestingly, days 3, 5, 10 and 12 result in comfort scores of 1.0 for the dressings, whilst 7 and 14 show the scores as 1.2 and 1.4 respectively – is it possible these higher scores were conveniently excluded from the analysis?

There are other examples of sloppiness that call into question the integrity of the research. In the introduction, a paper is cited as saying that nipple pain typically starts to decline by day 12. In fact, the study reported in this paper only lasted 7 days2 (this same error occurs in the ‘clinical case study’ reported on the manufacturers website – one can only assume the authors copied the reference without actually bothering to check it). We are told 11 participants dropped out of the study, but not which group they belonged to (they could all potentially have been using the dressings). It is also not clear why 30 people were ‘randomized’ to the dressings group, and 34 to the control group. Why not have 32 in each? A presentation at the International Lactation Consultants’ Association (ILCA) Conference describing the study in progress stated there were 30 women in each group3; why the control group then increases by 4 (unbalancing the design) is a mystery. This presentation also said that breastfeeding duration was being analyzed. Why is this data not provided?

Given that these less than convincing results are reported with great enthusiasm, you would be forgiven for thinking that this might simply have been a promotional exercise. And that, of course, is precisely what it is. Although it is described as ‘sponsored’ research, and discretely labeled as a ‘product focus’, it is not a study that would ever have been published with a negative result.

If you ignore the problems with the figures, and simply take the data at face value, it is possible that the dressings may have provided increased ‘comfort’ for some women. The difference between the scores of the two groups is less than a point, however, and could conceivably be down to experimenter bias, as the investigators conducting the study may have been keen to obtain a positive outcome for their sponsor. Even if the effect is genuine, it certainly does not translate into the substantial support for the dressings claimed in the article. The dressings are marketed as having moist wound healing properties, and although these are alluded to frequently, they are never actually tested. Previous research has shown that hydrogel dressings do not help nipple wounds to heal more quickly when women are breastfeeding, and may potentially foster infection4. When you consider it in this context, what initially appears to be genuinely useful research, may in fact be harmful propaganda.

  1. Br J Midwifery. 2004 Apr;12(4):244-248.
  2. Nurs Res. 1995 Nov-Dec;44(6):347-51.
  3. J Hum Lact 2004; 20; 211.
  4. Arch Pediatr Adolesc Med. 1998 Nov;152(11):1077-82.

Breastfeeding and thrush: the difficulty getting a diagnosis

stack-of-petri-dishesAlthough many lactation specialists agree that breasts are susceptible to thrush (the candida fungus) when a woman is nursing, others feel that the yeast infection is ‘overdiagnosed and overtreated1.’ A quick perusal of the Mumsnet discussion forum shows that some health professionals are prepared to go a step further, and deny it is a problem at all (see breastfeeding and thrush: it’s complicated).

The scepticism that thrush can interfere with breastfeeding exists because at present there is no absolute proof that candida is the root cause of breastfeeding pain. A mother can become colonized with candida but remain infection-free, or can display many of the symptoms commonly associated with thrush (such as red, shiny, flaky or burning nipples) but test negative for it in the laboratory2.

This doesn’t mean that thrush isn’t a problem however: there are several controlled clinical studies that point to an association – not a perfect one, but a significant one nonetheless – between the presence of candida and certain symptoms suffered by breastfeeding mothers.

Evidence that thrush can affect breastfeeding mothers

Support for this relationship was provided by a study that assessed whether mothers who tested positive for candida shortly after they had given birth went on to develop the symptoms of thrush2,3. Nipple swabs and milk samples that were taken from 100 women at their two week post-birth check underwent microbiologic culturing to test for candida, and women completed two interviews to determine whether they had symptoms associated with thrush: one at the time the swabs were taken, and another 7 weeks later.

Although there was no association between colonization and symptoms initially, 20 of the 23 women colonized by candida went on to develop at least one of the symptoms of thrush (burning nipples, stabbing breast pain, shiny and/or red nipples). The percentage of cases (breasts rather than mothers, as it’s possible to be affected on only one side) with a positive or negative candida result that developed symptoms are listed below.

Nipple culture results (22 positive cases, 178 negative cases):

  • 95% of positive cases and 49% of negative cases reported sore nipples
  • 100% of positive cases and 33% of negative cases reported burning nipples
  • 82% of positive cases and 18% of negative cases reported non-stabbing breast pain
  • 91% of positive cases and 24% of negative cases reported stabbing breast pain
  • 45% of positive cases and 11% of negative cases reported shiny nipples
  • 36% of positive cases and 13% of negative cases reported flaky nipples

Milk culture results (32 positive cases, 168 negative cases):

  • 78% of positive cases and 50% of negative cases reported sore nipples
  • 81% of positive cases and 33% of negative cases reported burning nipples
  • 72% of positive cases and 16% of negative cases reported non-stabbing breast pain
  • 81% of positive cases and 21% of negative cases reported stabbing breast pain
  • 41% of positive cases and 10% of negative cases reported shiny nipples
  • 38% of positive cases and 11% of negative cases reported flaky nipples

Every symptom occurred at a significantly higher rate in the cases where candida had been detected. Each symptom was also reported in several negative cases, however, indicating either that the mothers had become colonized by candida after the initial test, or that the symptoms were caused by something else.

Another study investigating the link between the results of milk cultures and breastfeeding pain also reported that candida was found in a significantly greater proportion of women who were suffering from sharp, shooting breast pain: 6/20 (30%) of the women with pain tested positive for it, but only 6/78 (5%) of the no pain group4. This study also tested for levels of common bacteria, and found they did not differ significantly between the two groups.

Evidence that symptoms associated with thrush may be caused by something else

There are other experiments, however, which indicate that bacteria – rather than fungi – may be the culprit in some occurrences of breastfeeding pain. A study comparing culture results of 20 women with deep, stabbing pain, 20 with superficial nipple pain and 20 controls with no pain found an association between candida and superficial pain, and bacteria and deep pain: candida was found on the nipples of 1 of the control group, 12 of the superficial pain group and 10 of the deep pain group; and in the milk of 1 of the control group, 10 of the superficial pain group and 5 of the deep pain group5. By contrast, pathogenic bacteria were detected on the nipples of 4 of the control group, 11 of the superficial pain group and 19 of the deep pain group, and in the milk of 6 of the control group, 8 of the superficial pain group and 14 of the deep pain group.

Support for the idea that thrush does not underlie all breastfeeding pain is also provided by a recent study that compared levels of candida in the milk of 18 healthy breastfeeding mothers and 16 with thrush symptoms (sore, inflamed or traumatized nipples, intense stabbing or burning pain and painful breastfeeding that had not received any other diagnosis)6. The investigators were very careful to avoid contamination of the sample: nipples were thoroughly washed, and breasts were pumped for 12 minutes before any milk was collected. No evidence of candida was found in any of the samples, leading the authors to suggest that it does not infect milk ducts, and is unlikely to be the cause of the symptoms associated with thrush. They also go a step further, and suggest that positive nipple cultures cannot be trusted, as they may be contaminated by the baby’s saliva, which often contains candida. They conclude that, ‘candida infection on the mother’s skin remains a possibility, but it seems unlikely.’

This interpretation of the results seems fairly extreme. In previous studies, candida has been found to colonize milk (but not nipples)2 so the possibility that thrush may infect milk ducts cannot be ruled out. It is also not really appropriate to draw conclusions from the data about candida infection of the nipple, or the role of bacteria in breast pain, as neither of these things was actually examined. There is some evidence that bacteria may underlie certain instances of breast pain – it has been found at higher concentrations than candida in the milk of women suffering from deep pain5 – but this result conflicts with another reporting higher levels of candida in women suffering from a similar complaint4.

It is not only the role of bacteria that is hazy, however: despite the association between candida and symptoms reported in some studies, this link is far from concrete. Not every woman with the symptoms of thrush tests positive for candida, and some who are colonized by it never report symptoms. If you also consider that cultures themselves can be easily contaminated and may therefore be unreliable, the picture gets even more complicated.

Treating the symptoms of thrush

What does all this mean for breastfeeding women who appear to be suffering from thrush? Some researchers take the view that as the relationship isn’t sufficiently proven, women should not be treated with antifungal medication, or should receive it only as part of a controlled trial7. Others take a more pragmatic view, and suggest that such medication can actually have a useful diagnostic value: if the symptoms clear up after using an antifungal, then this ‘confirms’* that the symptoms were caused by candida8. This is far from an ideal solution (using such medications unnecessarily is expensive and increases the chances of fungi developing resistance to them), but it may be preferable to leaving women to suffer with very painful symptoms when there is chance they could be cured. Women who exhibit the symptoms of thrush when breastfeeding are at a very high risk of giving up3, so if there’s a medication that could stop this from happening, it may not be a bad idea to use it.

  1. Breastfeed Med. 2009 Jun;4(2):55.
  2. J Hum Lact. 2004 Aug;20(3):288-95.
  3. J Obstet Gynecol Neonatal Nurs. 2005 Jan-Feb;34(1):37-45.
  4. Am J Obstet Gynecol. 2007 Oct;197(4):424.e1-4.
  5. Gynecol Obstet Invest. 1998 Aug;46(2):73-4.
  6. Breastfeed Med. 2009 Jun;4(2):57-61
  7. Breast. 2002 Feb;11(1):88-90
  8. J Hum Lact. 1999 Dec;15(4):281-8.

*Of course, this doesn’t really confirm that a mother was suffering from thrush, as the alleviation of her symptoms may have been coincidental.