Hey, baby! Why can't I massage out my blocked milk ducts or mastitis?

“I’ve been trying to massage out this clogged duct for the past week, each time I put her on the breast or when I’m in the shower or getting changed. I've even been using a Lactation Massager, one of those vibration devices, on the lump. But the blockage hasn’t gone away and worse, a couple of other lumps appeared. The first lump has become hot and red and hurts all the time. I had a high fever overnight and today I feel absolutely awful.”

Attempts to massage or vibrate away milk duct 'blockages' increase the risk of mastitis or abscess in breastfeeding women.

Mastitis means ‘inflammation of the breast’, but the term lacks international consensus when applied to lactation. It is conventionally understood to refer to an inflammation of the lactating breast characterised by a localised lump with erythema and pain. Systemic symptoms, including fever, myalgia, and rigor, may or may not be associated.

Mastitis affects about one in four breastfeeding women in the first six months postpartum, with 70% of cases occurring in the first eight weeks post-birth.^{1, 2} The incidence of mastitis varies widely across locations, which a recent systematic review suggests may be because mastitis is mostly preventable.²

Healthy lactating breasts are often lumpy, but these lumps decrease or disappear after breastfeeds.

A blocked duct has been described as a palpable and persistent lump which develops gradually, sometimes associated with localised tenderness or pain, in the absence of erythema or systematic symptoms. A blocked duct is best understood as a form of inflammation which is less severe than mastitis on the spectrum of benign inflammatory presentations in otherwise healthy lactating breasts, and which may worsen into a mastitis.

What causes blocked ducts and mastitis?

Excessively high milk pressures within the ducts and glands severely stretch or break apart tight junctions between lactocytes and duct epithelial cells, triggering inflammatory cascades (Box 1). Very high backpressures are caused by:

• Inadequate milk removal, relative to the woman’s rate of milk production, or
• Mechanical compression of the milk ducts.

As a result, there are two key steps for both prevention and treatment of blocked ducts and mastitis:

Step 1. Frequent and flexible extraction of milk

A milk ejection is accompanied by contractions of the alveoli and dilations of the ducts.^{3, 4} Milk ejections and milk removal occur in response to:

• Stimulation and negative pressures generated by
  • Baby suckling (which is the most efficient way to extract milk)
  • Breast pump
• Positive pressure generated by gentle hand expression.

Very frequent opportunities for milk removal result in frequent milk ejections (most of which aren’t felt by women).

Step 2. Elimination of mechanical forces which cause excessively high milk gland and ductal backpressures

These mechanical forces are:

• ‘Breast tissue drag’ (that is, stretching mechanical forces from a vacuum competing with the weight of the breast pulling in a different direction) during suckling or pumping, which both compresses ducts and causes nipple pain and damage;^5-7
• Deep mechanical pressure on the breast (lump massage or vibration) which causes
  • Ductal compression
  • Microvascular trauma, which causes microhaemorrhage and increased interstitial fluid, which worsens tissue swelling, which worsens duct compression and milk backpressure;
• Other focussed external pressure applications to the breast (e.g. breast shells, tight garment, massage towards the armpit).

When should antibiotics be prescribed for mastitis?

Current clinical protocols recommend antibiotics once mastitis (however it is defined) has been present for 12-24 hours, or immediately if the mastitis occurs in the presence of nipple pain.^{8, 9} But a 2013 Cochrane review found insufficient evidence to support antibiotics in the treatment of mastitis.¹⁰

In general, Australian doctors prescribe more than twice the amount of antibiotics relative to our European counterparts.¹¹ It is not surprising, then, that 77%-89% of Australian women and 86%-97% of United States women diagnosed with mastitis are prescribed antibiotics, with comparable rates in New Zealand and Canada.^12-14

But Scandinavian women diagnosed with mastitis or breast inflammation are much less likely to be prescribed antibiotics: 38% in a Finnish study and 15% in a Swedish study.^{15, 16}

In the latter 2007 study by Kvist et al, 85% of 210 episodes of mastitis in 205 breastfeeding women recovered without recourse to antibiotic therapy, having received help which included a fit and hold intervention, recommendation to increase frequency of breastfeeds, and daily phone follow-up so that women were more confident tolerating symptoms until they resolved.¹⁶ This study also showed that nipple damage did not increase the need for antibiotics, and that abscess developed in 3% of cases, regardless of antibiotic use. Regardless of country or rate of antibiotic prescription, abscess is found to develop in about 3% of women diagnosed with mastitis.^{14, 17}

A number of studies have shown decreased microbiome diversity and increased counts of Staphylococcus aureus in the milk of women with mastitis,^{2, 18-20} but recent human milk microbiome research also shows that the assumption that Staphylococcus causes mastitis and must be eliminated with an antibiotic is much too simplistic.^21-23

In a 2008 comparison of the milk of 192 women with mastitis or breast inflammation and 466 healthy breast milk donors, Kvist et al found no correlation between higher bacterial counts and symptoms. There were no differences in bacterial counts between those prescribed and not prescribed antibiotics, or those with and without breast abscess.²⁴

Fever is the body’s immune response to an inflammatory process and is not necessarily due to bacterial overgrowth or infection.²⁵ Aggressive fever suppression with anti-pyretics may even worsen inflammation.^{26, 27} High levels of leukocyctes and c-reactive protein in patients with mastitis indicate inflammation, not a bacterial load, and are not usually helpful investigations.²⁸  The 2007 Kvist et al study found that 52% of women presented with a fever, between 1-7 days after the onset of symptoms. But there was no association between fever at presentation and the need for antibiotics.¹⁶

Unfortunately, the presence of even small quantities of antibiotics in human milk alter microbial diversity and possibly the resilience of the maternal milk and gut microbiomes and the baby’s gut microbiome. Polymerase chain reaction (PCR) analysis shows that antibiotic administration reduces Lactobacilli and Bifidobacterium counts in human milk.²⁹

Over the past decade or more, the high rates of antibiotic use in women with mastitis has been challenged, noting the World Health Organisation’s urgent call for antibiotic stewardship in the context of the ‘slow motion catastrophe’ of global antimicrobial resistance.^{14, 24, 30} Antibiotics remain a treatment of last resort, when the signs and symptoms of breast inflammation accompanied by fevers persist without resolution over a period of days, or once the women’s symptoms are particularly severe.

What is evidence-based management of breastfeeding women with blocked ducts or mastitis?

The Neuroprotective Developmental Care (NDC) approach (Box 1) to the support of breastfeeding women makes the following recommendations for management of blocked ducts and mastitis:

1. Advise women never to apply pressure, vibration, or massage to a lactation-related breast lump. This includes avoiding Therapeutic Breast Massage and Manual Lymphatic Drainage treatments, which have not been shown to be effective (Box 2).³¹
2. Encourage very frequent flexible milk removal from the affected breast, either by baby’s suckling or by gentle hand expression or pumping. This could occur 12 or more times on the affected breast over a 24-hour period (though counting is not necessary), remembering that the baby should never be pressured to feed. Women will have the most milk ejections if they feed or express for shorter periods but much more frequently.³² Advice to ‘drain’ the breast by having long feeds followed by hand expression or pumping may increase supply beyond the infant’s needs and predispose to further mastitis.¹⁹
3. Ensure that any breast tissue drag during breastfeeding is identified and managed. Eliminating breast tissue drag during suckling is particularly important if the woman also has nipple pain or damage.
4. Advise as much rest as possible. Prudent use of ibuprofen may help with sleep at night.
5. If the woman is considering weaning, strongly advise against it right now, as weaning risks worsened breast inflammation.
6. Determine if the woman is pumping to create a supply that is in excess to the baby’s milk needs, as this places her at increased risk of mastitis.¹⁹ If so, she needs to continue to focus on frequent and flexible milk removal from the affected breast until recovered. Afterwards, recommend that she gradually cease pumping so that her supply downregulates to match the baby’s need.
7. A woman with a more generous breast could, without causing further pain, apply a flat palm gently to her breast and very gently mobilise the whole of the affected breast in various directions a few times a day. She might also stretch her arms out in various directions to mobilise the breast. Moving the breast with her palms may stimulate letdowns and help with milk removal, which likely to be the most important benefit. Both strategies move the breast tissue and support venous and lymphatic drainage. (A woman doesn’t require referral to a physiotherapist or massage therapist for this.)
8. Follow-up daily by phone after the initial consultation if the woman is feverish or her symptoms are severe, or provide regular follow-up until resolution.¹⁶
9. If antibiotics are required, prescribe flucloxacillin or dicloxacillin 500mg four times daily; cephalexin 500 mg four times daily if allergic to penicillin; and clindamycin if the patient is known to have an anaphylactic reaction to penicillin.⁸ Severe breast inflammation which doesn’t quickly respond to oral antibiotics requires hospitalisation for intravenous treatment.⁸

Other commonly used interventions for blocked ducts and mastitis, such as positioning the infant so that the chin or nose points to the area of inflammation, advice to ‘drain’ the breast, oral lecithin, probiotics, or therapeutic ultrasound, are not supported by evidence, and lack credible physiological explanations.^{22, 33-39} Management of the spectrum of presentations of lactation-related breast inflammation including approaches which don’t help is discussed in detail in two articles which detail the NDC approach to breast inflammation (currently under review).^{40, 41} 

Box 1. Hypothetical causes of lactation-related breast inflammation

Clinical breastfeeding support remains a research frontier, and much of the advice given to breastfeeding women lacks an evidence-base. It's been hypothesised that blocked ducts and mastitis are caused by ‘sticky milk’ which results from milk stasis. It's also been hypothesised that blocked ducts and mastitis are caused by fat globules clumping together and adhering to the ductal epithelium, or that bacteria form a biofilm which does the same, so that the milk ducts become narrowed or blocked up.⁴² It's been hypothesised that blocked ducts and mastitis are caused by retrograde spread of harmful bacteria from painful damaged nipples.^{2, 19} But there is no evidence to support the effectiveness of treatments derived from these theories, and when we look closely at human milk and skin microbiome and milk fat globule research, these theories remain unconvincing.

For example, lipids are emulsified in human milk within a sophisticated fat globule membrane, which protects against fat globule coalescence and the adherence of harmful bacteria.⁴³ As the volume of milk in the breasts increase, the concentration of fat globules decreases.⁴⁴ Biofilms are a normal part of healthy human microbiomes.⁴⁵ Research into pathological biofilm has occurred in the context of burns and vascular or diabetic ulcers and should not be extrapolated into the incredibly immune-rich environment of the lactating breast. The milk microbiome contains bacterial species also found on nipple skin and in the infant oral microbiome, regardless of whether or not there is nipple damage, and some have been identified in colostrum prior to the first breastfeed, perhaps due to translocation from the maternal gut. The human milk microbiome is best understood as an extension of, and in complex stabilising interactions with, the mammary immune system.^21-23

Breastfeeding women sometimes express stringy or solid milk substance in the context of blocked ducts or mastitis, but this is most accurately understood as a late-stage bi-product of inflammatory cascades, not the cause.

Two-thirds of the glandular tissue of the lactating breast is found within a three-centimetre radius of the nipple base, and ultrasound imaging has shown that milk ducts are very easily compressed by light pressure, similar to the way light touch compresses the veins on the back of a hand.^{3, 4, 46} There is a clearly established connection between nipple pain or damage and mastitis, but this is best explained by a common underlying mechanical cause. Conflicting intra-oral vectors of force (‘nipple and breast tissue drag’) concentrate very high stretching or bending mechanical loads upon parts of the nipple epithelium, resulting in nipple pain and damage. The same mechanical loads also occlude underlying milk ducts, resulting in backpressure within milk ducts and glands.

The early life care programs known as Neuroprotective Developmental Care offer a new mechanobiological model of lactation-related breast inflammation.^{40, 41} This model proposes that excessively high pressures in the milk glands and ducts, caused by increasing volumes of milk, result in stretching and breakage of lactocyte and ductal epithelium tight junctions, triggering inflammatory cascades.^{25, 47, 48} Increasing the frequency of milk gland contractions and ductal dilations (that is, milk ejection) in tandem with vacuum application (that is, suckling or gentle pumping of the breast) will relieve the backpressure, decrease the inflammatory dilation of blood vessels, and support lymphatic drainage of inflammatory interstitial fluids across the fluctuating stromal pressure gradients caused by frequent milk gland contraction and ductal dilations.

The approach to breast inflammation in this Hey, Baby! article forms one part of the clinical strategies offered in the breastfeeding domain of Neuroprotective Developmental Care (NDC or ‘the Possums programs’). The NDC breastfeeding domain is developed from:

• The gestalt biomechanical model of infant suck
• The mechanobiological model of lactation-related breast inflammation
• Evolutionary biology, and
• Complexity science.

Box 2. Why should women with blocked ducts or mastitis avoid Therapeutic Breast Massage and Manual Lymphatic Drainage?

Therapeutic Breast Massage and Manual Lymphatic Drainage include light massage towards the woman’s axilla, in the opposite direction to the pressure-gradient driven movement of milk in her ducts. Therapeutic Breast Massage alternates this with hand expression of milk. Proponents theorise that light pressure towards the axilla enhances the uptake of interstitial fluid into the lymphatic vasculature, relieving inflammation.³⁹ But the research concerning lymphatic micro-anatomy of the breast and mechanisms of lymphatic drainage of stromal interstitial fluid do not support this hypothesis.⁴⁹

A 2016 randomised controlled trial by Witt et al is often cited to prove the benefit of Therapeutic Breast Massage. Unfortunately, most women in the intervention group (25 of 40) chose not to follow up when approached two days after the intervention, and by 12 weeks, 27 of the 40 failed to follow up. In contrast, the control group had a 90% retention rate.³⁹ For this reason, Witt et al’s study doesn’t demonstrate that Therapeutic Breast Massage helps women.³¹

Manual Lymphatic Drainage derives from an approach to lymphoedema in the arm or breast which occurs after breast cancer surgery due to the removal of lymph nodes. Even in the case of post-surgery lymphoedema, Manual Lymphatic Drainage has not been demonstrated to be effective: the measured positive effects could be due to the compression bandages applied at the same time.^50-52 There is no evidence or mechanism to suggest that Manual Lymphatic Drainage is helpful for acute lactation-related tissue inflammation, which is markedly different to post-surgical lymphoedema.

Both massage approaches risk increased milk gland and duct backpressure and worsened inflammation. Any perceived benefit may be due to the milk ejections stimulated by gentle handling of the breast, which a woman can be empowered to achieve in other (much cheaper) ways.

Dr Pamela Douglas is a GP and Medical Director of Possums & Co. www.possumsonline.com, a charity that educates health professionals in the evidence-based Neuroprotective Developmental Care (NDC) or Possums programs, including the Breastfeeding Self-help Online Program. (This program is now available inside Milk & Moon, our exciting new home for parents. Milk & Moon membership includes everything in the Possums Baby and Toddler Sleep Program, the Gestalt Breastfeeding Program, and the Parent Hub, plus many additional resources. We are no longer selling these products separately, but as an all-in-one plus much more membership through Milk & Moon.) If you are a health professional, you can refer to or upskill to become an NDC-accredited practitioner. There are lots of free videos and other resources for parents with babies here, and online parent peer support is available for a nominal fee (also now available inside Milk & Moon). Pam is an Associate Professor Adjunct with the School of Nursing and Midwifery, Griffith University, and senior lecturer with the primary care clinical unit, The University of Queensland. She is author of The Discontented Little Baby Book: all you need to know about feeds, sleep and crying. This article belongs to the 'Hey, baby!' series published in The Medical Republic. 

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