23: The Mechanics of Breastfeeding

How does a baby’s mouth work in order to breastfeed? How does a baby use their mouth differently when they breastfeed compared to when they bottle feed? And how do infant feeding patterns shape your baby’s mouth and facial structures? Today we will talk about all of this.

A baby needs quite a lot to be intact and functioning properly in order to feed successfully and easily. Before we even get into the latch, sucking, or swallowing- I first want to point out that a baby requires more than their mouth and throat to eat. If they have difficulty breathing, difficulty getting comfortable, are feeling physically insecure, or have belly pain for example- it will be harder to focus on the task of eating. So first and foremost, they must have other body systems comfortable and working well. Assuming they are, let’s now talk about how a baby’s mouth works with breastfeeding.

Everyone always talks about a wide latch. “Oh you want a wide latch.” “The problem is that the baby's latch is shallow.” “ Oh, use the sandwich hold so your baby gets more breast in their mouth.” Etc. But why?

Well, it’s because breastfeeding relies heavily on negative pressure in your baby’s mouth (or oral cavity) in order to maintain a latch and stretch your nipple. Nipple stimulation and stretching, ductal pressure, and a whole bunch of hormones dancing within your body, are primary drivers in not only milk production- but also for milk ejecting out of your nipples. (This is commonly called “let down”.)

To understand this let’s first imagine negative pressure. When you suck on a straw, you are creating negative pressure in your mouth. A child’s medicine syringe pulls liquid into itself due to negative pressure.

Negative pressure can only be created in a sealed environment. So a baby with a cleft palate for example, will not have a closed space to create negative pressure. Same goes for a baby with a very low tone who cannot maintain a sealed connection between their lips, tongue, and the breast. In both of these examples, air would be able to escape from somewhere in and out of the baby's mouth.

Most babies do not have these issues and when they latch to the breast, they get going to create negative pressure so they stay latched and milk flows.

A wider latch allows more breast tissue to be in a baby’s mouth. It positions the nipple deeper in the baby’s mouth thereby avoiding compression on the nipple which can happen with a more shallow latch.

So when babies have a wide latch they have more than just the nipple in their mouths. They have the nipple as well as the areola and some other breast tissue in their mouth.

Once latched, babies suckly and stimulate the nipple which sends the message to your breasts to move the milk. When milk starts ejecting from your breasts (or “letting down”), your baby will change the pattern of their movement and get into a suck-swallow-breath cycle.

Babies move both their jaw and their tongue downward, creating negative pressure and space for the nipple to stretch toward the back of their mouth. As the jaw moves down and then up, the tongue will also move down and up with it. During this, the front end of the tongue will maintain contact with the breast by being cupped around it. This serves as sort of an anchor, and also helps maintain a connected latch.

With a shallow latch, there’s less space for the nipple and areola tissue to stretch. There’s less jaw and tongue movement downward. The gums and hard palate are putting more pressure on the sensitive nipple, usually it’s getting mashed on the hard palate. And this changes how the nipple and breast tissue would move within the mouth.

Let’s assume there is a nice wide latch, which may take a little practice and that’s okay. And let’s assume the baby is creating the appropriate negative pressure to elicit milk expression.

Each time milk comes into their mouth, and they have a mouthful to swallow, they will then create positive pressure. To squeeze the milk to the back of their mouth. They do this by first lifting their jaw and tongue up. Then, their tongue moves in a wave-like pattern from front to back to squeeze (or push) the milk back to swallow.

So adequate range, tone, movements, and some practice are all needed to get the oral mechanics of breastfeeding working smoothly. 

Once a pattern of movement is established and repeated day after day, feed after feed, it will help to shape the mouth and face. This makes sense though right? If you sit a certain way day after day, your body starts taking on that shape. If you workout or move your body over and over a certain way, over time it starts to take on that shape.

It’s the same with the oral cavity. How your baby eats, breaths, and uses their mouth repeatedly impacts how it will be shaped. Breastfed babies engage their masseter jaw muscles more during feeding, then bottle fed babies. They are, with each feed, developing their jaw which will impact the shape of their palate as well as dental spacing.

The oral cavity also impacts the nasal cavity because the palate which is the wall between the nasal and oral spaces is impacted by oral posture and movement. 

Have you ever met someone who is a chronic mouth breather? They may actually have a longer face, lower facial tone, and smaller nasal cavity if this is a chronic pattern for them.

Repeated movements shape us. So is the case with how we eat, the overuse of pacifiers, overuse of pureed pouch food, not getting developmentally appropriate oral input, chronic mouth breathing, etc.

What we practice long term and daily shapes us and this is something to consider for many developmental stages so we want to give babies opportunities that point in a positive direction wherever we can.

Breastfeeding is a great way to do that, but I understand it’s not for everyone and that there are a variety of reasons why a child may be fed another way.

Regardless of how you feed your baby, remember to include other positive oral experiences like allowing them to mouth their hands, safe objects, and safe foods as appropriate. And gradually working toward a variety of textures once they are practicing solid foods and are ready, is also great ways to support oral development.

I hope this episode expanded your understanding of the oral mechanics of breastfeeding, how a wide latch impacts it, and how feeding patterns help shape our facial structures. 

Please consider taking a quick moment to rate or share the show, and next week I will be back so we can chat about what things can be a barrier to that wide optimal latch.