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.

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.

Breastfeeding and thrush: it’s complicated

woman-doing-mathI sometimes feel as if I’ve experienced pretty much every breastfeeding problem going: sore/bleeding/fissured nipples; mastitis (although fortunately only the early stages); not enough milk; too much milk; and a very temperamental let-down reflex. One of the only things I haven’t suffered from is thrush – a fungal or yeast (candida) infection that allegedly causes excruciating nipple and breast pain. I use the word ‘allegedly’ simply because it is not always easy to determine whether the symptoms associated with thrush are definitely caused by a fungal infection, or whether they are in fact down to something else. I am not a thrush doubter – I think there is sufficient evidence to justify taking it very seriously, as does the NHS. Many health professionals who do not specialize in breastfeeding are yet to be convinced, however, as the Mumsnet discussions below testify:

(These are just a drop in the ocean – you will find all manner of breastfeeding ignorance from health professionals on these noticeboards. The GP who suggested a mother might pass mastitis on to her baby deserves a special mention.)

It isn’t just those outside the field who disagree about thrush: within the scientific literature there are conflicting results and opinions, as well as holes in clinical knowledge because the relevant research simply hasn’t been conducted. I’m currently wading through the published work in this area, and am finding it’s actually quite difficult to get to the bottom of the relationship between yeast infections and breastfeeding problems. As it’s important to try to make sense of it though, I’ll be writing several posts on it over the next few weeks, starting with one that attempts to address the controversy that still surrounds the diagnosis.

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