It takes two: Impact of infant oral anatomy on breastfeeding | Jaw

When people hear the word 'breastfeeding,' I will bet that the first thing that comes to mind is breast related.

Breasts. Mammary glands. Milk. Mother.

Pretty much the idea of breastfeeding seems pretty set around the parental experience of feeding babies human milk.

In today's post, I want to focus a bit more on the baby's perspective, and the impact that oral anatomy has on their feeding ability. There are lots of mouth-parts to look at, but I will be only discussing the lower jaw (mandible) today.

I have a particular interest in the impact that anatomical influences have on an infant's feeding ability. It's something that is not discussed nearly enough and something that provides a great challenge for many parents.

Many feeding challenges, be it at the breast/chest or bottle, have to do with oral function, which is directly influenced by oral anatomy.

Effective feeding takes the coordination of a series of complex skills. Anatomical differences can pose a serious challenge to a baby's ability to accomplish these required skills in a way that makes for safe and effective feeding.

I think a quick (and basic) anatomy overview might be helpful.

There are over 21 muscles used in infant feeding!

You can see why I need to break this topic up in smaller, more easily digestible pieces.

The mouth can be broken down into three separate parts: The top part which consists of the upper gum ridge, maxilla , hard palate, and soft palate, the bottom portion, which includes the jaw (mandible), lower gum ridge and tongue, and the back portion which we won't be addressing at all in this post.

A baby's lower jaw is generally short, as it's growth tends to be inhibited by the chin to chest position babies take in utero. To compensate for the short jaw, babies' anatomy tend to favor jaw opening over jaw closing, allowing for an easy, drop down in jaw position and a wide gape.

The mandible plays a significant role in feeding ability. It provides positive pressure during swallowing as it rises to the "closed mouth" position and creates negative pressure as it drops down during suction.

The mandible must be in good contact with the breast to take advantage of the full mechanical function needed for proper sucking. Babies naturally lead with their chin during latching and need to have the lower half of their face in contact with the breast to find the nipple on there own.

If you want to learn more about the latching process, I recently covered this in the Science Of Latching. It's worth checking out in my opinion.

So now that we know the jaw's role in infant feeding, let's look at a few situations that may make feeding a challenge.

The following list include some of the most common jaw conditions that may impact the ease at which a baby can feed with breast/chest or bottle:

• Retrognathia

• Micrognathia

• TMJ Dysfunction

• Prognathia

Retrognathia:

Retrognathia occurs when the baby's jaw (mandible) is pulled too far back.

Imagine a super insane overbite.

Mostly all babies have a recessed chin of some sort, this is entirely normal and expected. Mandible growth for all babies is rapid during the first three months, so many babies with retrognathia can breastfeed well by or soon after three months of age.

A mild case of retrognathia may pose little challenge to a breastfeeding parent-baby pair, possibly only requiring positional changes.

Prone positions, where a baby is on their belly such as in biological or laid back nursing, can be quite useful in helping bring the jaw forward.

We use the forces of gravity when possible :)

Babies that have severe retrognathia may not be able to breastfeed at all due to an inability to manage breathing while nursing, as a recessed jaw can impact their airway.

In these cases, bottle feeding with specialty bottles may be indicated. A baby's feeding position is important for bottle feeding as well, with elevated sidelying and high cradle being good options.

Retrognathia can sometimes be confused with tongue tie, but it's essential to note that in certain circumstances, a frenotomy may be contraindicated in some babies. The potential of airway obstruction due to the "tongue falling back" is increased if the lingual frenulum is released in some cases.

Directly nursing babies with retrognathia can be painful.

The fact that the maxilla and mandible are out of alignment by quite a bit can cause the nipple and areola to be compressed against the hard palate. Additionally, tongue elevation and retraction of the back portion of the tongue can be inhibited, causing a reduction in suction pressure needed to feed efficiently. Babies may try to compensate due to the lowered vacuum pressure which can result in pain.

In either case, friction and irritation can result and where there is friction, there is pain!

Micrognathia

Micrognathia is a condition that affects the size of a baby's jaw (mandible). There is no set definition for what constitutes micrognathia, but generally speaking, micrognathia is used to describe an excessively short jaw vs. a jaw that is just pulled too far back.

The difference between micrognathia and retrognathia can be confusing.

You can think of micrognathia as describing the actual size of the mandible (short and small) and retrognathia as a positional description (too far back).

Whether it's retrognathia or micrognathia, the situation will be similar.

With micrognathia, however, the lingual frenulum tends to be attached closer to the lower gum ridge, usually resulting in a restriction of the mid- and posterior portion of the tongue. Baby's with micrognathia tend to elevate their tongue tip and hold that portion of the tongue to the hard palate. This may be due to a lack of room in the oral cavity for a normal tongue resting posture. The elevated tongue position, along with an extended neck position, helps to stabilize a baby's airways, as just like with retrognathia, airway management can be an issue with micrognathia.

Asymmetrical latching positions are essential for babies with micrognathia. Side lying and prone positions may allow for better head extension. In cases like these, prone nursing positions are your friend.

Tip: Try a modified prone kneeling position to bring the jaw forward and to help baby manage milk flow.

TMJ Issues

Birth Induced TMJ Dysfunction is reported to be the most common cause of breastfeeding difficulties, according to ICPA. Now I must note that that little fact seems to be a chiropractor related fact, one that I never see mentioned in lactation literature.

Regardless if it's the most common cause of feeding challenges or not, TMJ issues in infants can pose a problem with feeding.

TMJ can look like tongue tie when talking about functional limitations but usually, with TMJ there may be audible noises from the jaw during feeding, and you may be able to feel the "jumps" of the TMJ during jaw movements.

Babies with TMJ issues need a bit of support on the jaw, either under it (such as the dancer hold) or slight pressure at the actual Temporomandibular joint. Babies tend to feed better when their affected size is supported, so it may take some creativity to find a position that works best for you and your baby.

Prognathia

Prognathia is the opposite of retrognathia and something that I am not super familiar with myself. I may try to dig more indepth on the subject to see what I can find, but this is what I know:

Prognathia is when the jaw is protruding too far forward. Babies with prognathia may do better in supine (on the back) positions that pull the jaw back slightly.

Again, we're using gravity to our advantage.

Other than that I have no experience and little knowledge on it. Although I have it listed as one of the more common jaw issues in babies, it isn't common at all.

The key to remember with breastfeeding, and the thing I hope you take away from this post is that two people (parent and baby) need to be considered when discussing breastfeeding and lactation.

Milk feeding directly at the breast/chest is affected as much, if not more, by variations in infant anatomy as it can be influenced by the differences in the anatomy of the milk feeding parent(s).

Want a better understanding of your baby’s feeding strengths and weaknesses? Click here to learn more about the FREE DIY oral assessment worksheet.

This topic is vast and one that someone could devote countless hours studying. I hope that presented this introduction on the subject in a way that not only sparked your interest but was easy to understand.

If you have any questions or concerns, as always, I would love to hear from you. :)