How breastfeeding works

Breastfeeding isn't always plain sailing.  An understanding of the mechanics of the process shows that when problems do occur, they are often a consequence of poor positioning and technique. Caroline Green explains.


The exhausted, happy, bewildering (and uncomfortable) days of early parenthood can pass in a blur for many first time mothers. Advice comes in thick and fast at a time when you may feel least equipped to absorb it.

Maja with Leon (breastfeeding) - Maja z Leonem (karmienie piersia) PREV.jpgMost mothers, however, are aware of the breast is best’ message even before birth. There is no doubt that breastfeeding offers a wide range of immediate and long term health benefits for both mother and baby. Breastfed babies have less chance of contracting vomiting and diarrhoea bugs, get fewer chest and ear infections, have a lower chance of becoming obese and all the illness that are associated with it, and less chance of developing eczema. Breastfeeding mothers have a lower risk of breast and ovarian cancers.

Unfortunately, the UK has traditionally lagged behind many other European countries such as Norway, Sweden, Denmark, Italy, Spain and Switzerland in its breastfeeding rates, although the good news is that there has been an improvement in recent years. According to the NHS Infant Feeding Survey, the proportion of babies breastfed from birth has increased from 76% to 81% since 2005.

But many mothers are still choosing not to breastfeed, or may give up during the early weeks of their baby’s life. There could be a range of reasons for this, ranging from pain and discomfort to concerns that the baby is not thriving as they believe it might on formula milk. It may often come down to a lack of support in those early days.

Breastfeeding expert Dr Mike Woolridge, Senior Lecturer in Infant Feeding School of Healthcare at the University of Leeds, says it is important to remember that, ‘Breastfeeding “works” 999 times out of a thousand. If it didn’t, we would not be here as mammals on this planet. This is a process that has worked in mammals for millennia.’

That is not to say that it is always plain sailing. But an understanding of the mechanics of the process shows that when problems do occur, they are almost always a consequence of poor positioning and technique.

And that means these problems can almost always be rectified.

Babies are actually born knowing what to do. They will have had several weeks of practise in the womb, sucking and swallowing amniotic fluid.

In his paper, “The ‘Anatomy’ of Infant Suckling” Dr Woolridge says, ‘Whilst the mother has to develop the essential skills for breastfeeding, the newborn comes equipped with two specific innate reflexes to help him obtain the nutrients essential for survival.’    These are the ‘rooting’ reflex, where the baby turns its head to its mother’s breast, and also the way a baby’s mouth will gape open, ready for the nipple. In its first few days in the world a baby will only gape only briefly, but if this is reinforced repeatedly with a milk ‘reward’, before long the baby’s mouth will simply drop open like a trap door in response to feeding cues.

However, it is unhelpful for new mothers to believe that they too should have an innate knowledge of how to breastfeed. ‘Contrary to popular belief,’ says Woolridge, attaching the baby to the breast is not an ability with which the mother is innately endowed; rather it is a learned skill which she must acquire by observation and experience.’

So what actually happens when a baby takes its mother’s breast into its mouth?

Once the nipple is correctly positioned, feeding occurs by a process of peristalsis. That is the wave-like motion seen elsewhere in the body during digestion. The tongue, jaw, lips and palate are all part of the process.

Here is the process in detail:

  • The baby draws your nipple and much of the breast tissue lying behind your areola into his/her mouth.
  • The lower jaw is raised to constrict the base of the nipple and the front tip of the tongue wells up to compress the breast against the roof of the mouth.
  • Waves of compression by tongue move along the underside of the nipple, pushing it against the hard palate. This roller-like action squeezes milk from the nipple through the middle of the mouth and to the back.
  • Recent evidence suggests that your baby can also suck slightly more strongly at one key point in the sucking cycle, probably to enhance milk flow, although this tends to be mainly in the middle of the feed (i.e. not the start when your milk is flowing well, and not at the end, when your baby is feeding in short bursts with long gaps in between).
  • The same wave of compression by the tongue is also responsible for pushing the milk towards the back of the baby’s mouth for swallowing. As it does this, it pushes the soft palate up and out of the way, so that the milk spills into your baby’s gullet.

There has, however, been some controversy among academic circles over this issue of precisely how the milk moves through the baby’s mouth.

Scientists in Perth, Australia recently published a paper that highlighted the suction element mentioned above. But the team at the University of Western Ausuckling - a baby's peristaltic feedingstralia have discounted the peristaltic model entirely and say that milk removal is solely down to this suction action. They say there is no milk flow before or after the point at which the baby delivers deep suction pressure.

Woolridge argues that while there may be an element of this during the process, it is quite wrong to deny the role of peristalsis completely, as the Perth team appear to have done. He equates the issue with breathing. We breathe naturally and without thinking all the time, but sometimes we will deliberately take in a deep breath. In the same way, a baby will be feeding peristaltically as a matter of course, while occasionally using suction to prompt a deeper drink.

It may sound as though the squabbling of academics has little to do with the practicalities of breastfeeding for most mothers, but if you follow the peristaltic view, as Dr Mike Woolridge and a host of other experts to, then there are very few breastfeeding problems that cannot be solved by correct positioning and technique.

This is surely good news for mothers.

Conditions such as tongue tie, cleft palate and floppy larynx (see glossary) can make it much more difficult, but even in these cases there may be procedures or techniques that can be employed to help a baby breastfeed.

Interestingly, Woolridge’s team found that babies tend to feed in the same way whether they are newborn or several months old. ‘We studied babies from one week to sixteen weeks and we saw absolutely no age-related changes. It was really surprising. In fact, we saw that babies have a characteristic style of feeding at sixteen weeks and there was no change at sixteen weeks. One small difference may be that, as mentioned above, seasoned feeders will have a gaping motion almost like a hinge has been employed. When their mother perhaps gets into position or starts to rearrange clothing for feeding, the baby’s jaw drops automatically, ready to feed.

Another surprising find of the research was that babies don’t appear to use a different technique when they switch to a bottle. However, there have been no definitive studies on this issue as yet.

So what is the optimum feeding position? How do you avoid painful, cracked nipples and the problems associated with a baby that doesn’t seem able to latch on?

It is useful to think of the milk ducts as very thin, flexible versions of drinking straws. If the straw is crushed anywhere along its line, the drink will not flow. So the trick is to make sure the baby’s mouth is directly in line with the nipple. If the baby is having to twist its head acutely, or if the chin is pointing down, then this will almost cause a kink in the duct, a little like blocking the flow from a drinking straw.

Woolridge says it is crucial that the baby is at the right height to feed. ‘Put the baby where the breast naturally lies rather than pulling the breast over to where the baby is.’ Sit sit your baby on your lap with its head and body just slightly rotated. This way, the baby should be able to access the milk in a way that will maximise flow.

Sadly, it seems that the majority of mothers who give up breastfeeding do so in the very first week, which suggests that they may have simply needed a little more support in those early days. The rest who give up do so in the period between two to eight weeks.

There has, as stated above, been an improvement in drop-off rates in recent years. Up to a quarter of mothers used to give up in the first six weeks and that figure has dropped to 15-20%, largely thanks, says Woolridge, to the the efforts of the Baby Friendly Initiative and the work by the La Leche League. The ‘baby cafes’ that have sprung up in some areas, where mothers can share tips have also been helpful, he believes.

There is help available, even if it isn’t always immediately to hand.

The benefits of this amazing natural process are such that it is worth working on that technique and positioning until breastfeeding falls into place. Follow your instincts and ask for help where needed. And remember, as Mike Woolridge says, ‘By the time your baby is five days old, you will be the world expert on your child.’


Areola = The darker coloured skin immediately around the nipple.

Baby Friendly Initiative = A worldwide programme of the World Health Organization and UNICEF. It was established in 1992 to encourage maternity hospitals to implement breastfeeding programmes.

Cleft palate =  A gap or split in either the upper lip or the roof of the mouth or sometimes both. It occurs when separate areas of the face do not join together properly when a baby is developing during pregnancy.

Floppy larynx = A congenital softening of the tissues of the larynx (voice box) above the vocal cords. It is the most common cause of noisy breathing in infancy. The medical term for this is Laryngomalacia.

La Leche League = An international charitable organisation founded to give information and encouragement, mainly through mother-to-mother support, to all women who want to breastfeed their babies.

Palate = Roof of the mouth

Peristalsis = Wave like motion caused by muscle contractions.

Rooting = The reflex in newborn babies that prompts them to turn their faces towards their mother’s breast and make sucking motions.

Suckling = Experts would like to see the term ‘suckling’ being used more frequently for when a baby is feeding in the peristaltic way.

Tongue-tie = A problem that occurs in babies who have a tight piece of skin between the underside of their tongue and the floor of their mouth.

Further advice and help:

National Breastfeeding helpline: 0300 100 0212

Click here for links to breastfeeding support organisations.



Caroline Green pic (2).jpgAbout the author:

Caroline Green spent many years as a science and health journalist
and is an accomplished author of award-winning books for young adults.