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‘Unravelling the Mysterious Milk Ejection Reflex’

LCGB Conference April 2023: 'Unravelling the Mysterious Milk Ejection Reflex' By Sue Jameson IBCLC, FILCA

It was brilliant to be back at a face to face conference in the UK last month. LCGB, our sister organization, had invited a selection of speakers covering many integrated topics over the weekend. The theme was ‘ From Science to Practice’.

Someone well known to us in ALCI, Lisa Marasco MA, IBCLC, FILCA uncovered the mysteries of the milk ejection reflex on Day 1 and engaged us all on Day 2 to look at Unsolved mysteries of the Mammary Gland.  I am going to attempt to give you an outline of Lisa’s complex talk on Unravelling the Mysterious Milk Ejection Reflex.

Anyone working with lactation folks have seen a variety of situations where the milk ejection reflex is slower than we would wish, faster than the mother would wish and in some cases, absent to a great extent.

Lisa provided a detailed description of the physiology of Milk Ejection, citing the work of Kerstin Uvnas Moberg from her book Oxytocin – the biological guide to motherhood, and many other references, which I can make available to anyone interested in reading more on this complex subject.

So what does suckling do? It induces the release of local peptides, which in turn relaxes the opening of the milk ducts and blood vessels in the skin overlying the mammary glands – the familiar ‘red flush’ we are accustomed to seeing on a breastfeeding person's chest area. Oxytocin is released into the circulation and causes the contraction of myoepithelial cells. This in turn triggers activity in the brain, which downregulates the sympathetic nervous system. This means a lowering of fear and anxiety in the parent, which further downregulates the Sympathetic Nervous System. All the actions above increase the skin temperature and cause the Milk Ejection Reflex to activate.  There are so many actions and reactions involved in milk ejection that it is easy to see how the system can be influenced at so many different stages during the process. As IBCLCs we need our best sleuthing skills to get to the bottom of issues faced by our clients when it comes to problems with milk ejection.

So why does MER not always work reliably?    The three main areas of investigation are :

  1. Physiological - subdivided into hormonal/metabolic and Mechanical reasons.
High BMIPoor quality of suckling stimulation
Hypertension/pre-eclampsiaUnusual nipple & ductal anatomy
Thyroid dysfunctionNerve subluxations
DiabetesBreast nerve damage from surgery or accident
 Spinal cord injury
  1. Pharmacological
Tocolytics ?
Magnesium ?
Oxytocin in Labour ?
  1. Psychological – subdivided into Pain or noxious stimuli and psychosocial
Pain or Noxious stimuliPsychosocial
Postpartum painChronic stress
Latch painAnxiety/PTSD
VasospasmsAdverse early experiences (ACE)
Breast/nipple traumaDepression
BitingRace & poverty
Partner abuseGrief & loss
 Negative or chaotic environment

So what do we know? That milk production  and milk yield are not the same. Parents perception of supply is based solely on yield in many cases.

Oxytocin is essential to milk production as well as delivery.

The vagus nerve – cranial nerve X often called the wandering nerve operates outside the spinal nerve. Stimulation of this nerve by stroking (in rats) gives immediate increase in oxytocin

Alveoli don’t contract all at the same time – the fuller they are, the more sensitive to oxytocin.

There are a range of sensations felt during MER which can vary from barely felt to painful.

The closer the mammary tissue is to the nipple, the diameter of the ducts, milk density & viscosity, elasticity of tissue and infant suck all play a role.

Oxytocin release can be longer or shorter bursts and can vary in number, with the first couple yielding the most milk.

Exposure to stress during nursing resulted in significantly fewer oxytocin peaks

Genetic make up plus early life experience affect oxytocin function.

So how does labour and birth impact on Oxytocin and MER?

It would appear that oxytocin given in labour is related to natural levels on Day 2. The more Oxytocin given in labour, the lover the  level of natural oxytocin on Day 2. It is temporary and may interfere with feedback mechanisms. Jonas 2009

Epidural administration is also linked to a higher risk of disturbing the oxytocin mechanism.

Active management of Stage 3 of labour also implicated in reduced duration of breastfeeding (Brown A & Jordan S (2014)

Problems with C Section.  Stress activation in emergency situations. With elective, no priming of oxytocin system and slower initiation of breastfeeding. Wang Y (2019)

So how can we help?

Get our best investigative heads on and look for source of inhibition.

Work towards creating an environment of safety, relaxation & confidence

Help parents to reduce anxiety by avoiding data collecting and help them to focus on being present, responding to their baby in the here and now.

Teach stress reducing techniques and above all reinforce successes and positive thoughts. It is possible to press the re-set button and improve positive conditioning of the let-down reflex.

Using relaxation therapy, hypnotherapy, acupuncture, acupressure, reflexology, breast massage, warmth, baby wearing, skin 2 skin, breast compression, and massage  can all help to improve MER and oxytocin response.

There is also a place for herbal and other pharmaceutical remedies known as oxytocics.

Lisa also reckoned it was time to revisit the use of nasal sprays. She shared a selection of RCTs (Randomised Control Trials) which clearly demonstrated a place for pharmaceuticals in this arena.

Sue Jameson, May 2023. 

Sue received a bursary of €200 from ALCI to attend the LCBG Conference in the UK.