Why Tongue-Tied Babies May Show Slower Weight Gain as They Grow
When feeding looks “beautiful” but problems are still present
One pattern I see time and time again in clinic goes something like this:
Sometimes feeding doesn’t just look okay, it looks beautiful and sounds beautiful too. A tongue-tied baby can latch well, feed often and gain weight in the early weeks after birth.
At the same time, I also frequently see tongue-tied babies cause significant nipple pain and trauma for their mama in those early weeks.
Many mothers are reassured that this pain is normal, that nipples will “toughen up” and that as long as their baby is gaining weight, feeding is fine. So they persevere. And often, the nipples do heal after a couple of weeks. The pain settles and feeding feels more manageable.
However, while nipple pain may improve, the underlying feeding mechanics of a tongue-tied baby often remain unchanged. As babies grow and their feeding needs increase, this is where things can begin to shift.
Why changes often appear around 4–6 weeks
Around 4-6 weeks of age, feeding becomes more demand-driven. Babies need to work harder and more efficiently at the breast to maintain intake and growth.
This is often when parents begin to notice changes such as:
clicking at the breast
milk spilling or leaking
gulping or choking
reflux-like symptoms
feeds becoming longer, or instead shorter, fussier and more frequent
Weight gain may begin to slow, and babies can fatigue more easily during feeds.
What once appeared to be a resolved issue because nipple pain disappeared now starts to show up in the baby and on the growth chart.
In these cases, early nipple pain and trauma were often the clue, not a phase. It was a sign that the baby was compensating during feeds. Yet, as their needs increased, that compensation became harder to sustain.
Why the early weeks can look “fine”
In the first couple of weeks after birth, breastfeeding is largely driven by hormones. Milk comes in and flow is often generous, sometimes more than a baby actually needs. Letdowns can be strong, which means many babies are able to get what they need without having to work very hard.
This is why a tongue-tied baby can sometimes appear to feed “well” early on. They may feed frequently, appear settled at the breast (though not always) and gain weight within expected ranges. This can feel reassuring for parents and families are often reassured by healthcare providers based on early weight gain alone. As a parent, it makes complete sense to believe that everything is going smoothly.
However, this early “good start” can sometimes mask feeding inefficiency. A baby may be compensating in the early weeks. As they grow, their needs increase, and if their body is already holding tension, that tension can build further. The early weeks often hide these challenges well.
What changes as babies grow (and what I often see in practice)
As babies grow, their feeding needs increase and feeding becomes more physically demanding. Babies rely more on their own oral strength, coordination and endurance to keep feeds effective and comfortable.
This means, babies need to maintain a secure seal at the breast or bottle, generate and sustain suction, coordinate tongue and jaw movement and keep going without tiring out. When there is a tongue tie or oral restriction, this is often when feeding begins to feel harder. What was manageable in the early weeks can become more challenging as baby’s strength and stamina are tested.
In my practice, I also often see muscle tension play a significant role at this point. Babies may carry tension from their time in the womb, from assisted or fast births or from the compensations they’ve been making due to oral ties. This tension doesn’t always ease on its own.
Around 4-6 weeks, which commonly coincides with a baby’s second growth spurt, that tension can actually become more noticeable. As babies grow quickly, their muscles are asked to do more, but if a baby is already compensating, those tight little patterns they’re holding can increase rather than relax. This can affect how freely the jaw, neck, shoulders and tongue move during feeding, making feeding feel harder just as baby’s nutritional needs are increasing.
This is why we often see clicking occurring during this stage or babies no longer able to sustain a constant latch at the breast. They may lose suction quietly, rely heavily on jaw or neck muscles, tire more easily or swallow more air (hello, peak colic and reflux!) From the outside, feeds can still look frequent or even long, but milk transfer may be less efficient than it appears.
Over time, this can create a mismatch where the effort of feeding begins to outweigh the calories gained. As babies grow and need more milk, this imbalance can start to show up as slowed weight gain, changes on the growth chart and increasing feeding or reflux-related challenges. Often, this is when mother’s are told to either begin triple feeding, “topping up” or to give formula, as their milk supply is not sufficient. Yet, the milk supply isn’t always the issue - it’s how the baby begins to struggle to transfer the milk due to their restricted tongue and oral function.
Reflux and digestive symptoms often appear alongside
Around this same stage, I often see reflux or reflux-like symptoms become more noticeable, particularly in babies with tongue ties or feeding inefficiencies. This may look like frequent small spit ups or vomiting, silent reflux, gulping or choking during feeds, arching, unsettled behaviour or discomfort when lying flat frequent hiccuping or sneezing or raspy/hoarse audible breathing.
When feeding requires more effort, babies will usually swallow more air or struggle to stay relaxed at the breast. Combined with gut immaturity and increased muscle tension, this can make digestion harder and feeds more uncomfortable. Over time, reflux symptoms can shorten feeds or interrupt feeding rhythms because the baby is either too uncomfortable or struggling to breathe whilst feeding (due to a stuffy nose/nasal congestion), which can further affect milk intake and feeding efficiency.
For many families, I often say to them that silent reflux/reflux is one of the first signs that something about feeding mechanics or oral function needs closer attention.
Why all of this can affect weight gain and growth
When we look at changes on a baby’s growth chart, it’s rarely just one thing causing the shift. More often, it’s the combined effect of feeding efficiency, oral function, body tension, digestion and comfort.
If a baby is working harder to feed due to a tongue tie or other oral restrictions and tension, carrying muscle tension, swallowing more air or feeling uncomfortable from reflux or gut irritation, feeds can become more tiring and less efficient over time. Even when feeding happens often, milk transfer may not keep up with a growing baby’s needs.
At the same time, increased effort, discomfort and frequent unsettled feeds can raise stress levels in the body. This can further impact digestion, feeding rhythms and overall energy balance (think of how exhausted a little one gets after a crying episode - imagine doing it often throughout the day).
Together, these factors can create a situation where a baby is expending a lot of energy feeding, but not consistently taking in enough to support steady growth. Over time, this can show up as slower weight gain or a drop in percentiles on the growth chart.
This doesn’t reflect a lack of milk, effort or care on a parent’s part. It reflects a baby’s very small system that has been working hard for some time and needs support to become more efficient and comfortable.
This is also why being told to simply pump to “increase supply” or to routinely “top up after feeds” isn’t always the right answer and isn’t always supportive of a mother’s feeding goals. When feeding mechanics and comfort are the underlying issue, addressing the how of feeding is often more helpful than just adding more milk volume to a little one’s feed just so they can “gain weight.”
Brenda’s takeaway message
If there’s one thing I want parents to take from all of this, it’s that slowed weight gain or feeding struggles are rarely about the effort you are putting in or how much breastmilk you have.
I often explain it like this: expecting a baby to simply take more milk when their feeding mechanics aren’t working properly is a bit like asking a child or an adult with a swollen or sprained ankle to just walk more and “she’ll be right.” They might push through for a while, but the ankle is already inflamed and strained. Without the right support and proper alignment, every step takes more effort and can make the swelling worse.
Oral ties and feeding challenges work in a similar way. When a baby’s tongue and oral structures aren’t moving freely, feeding becomes harder work. Adding more milk (and/or even thickener) can help short term, if we’re just looking at the scales, but it doesn’t address the underlying strain or why your baby’s feeding has felt difficult in the first place.
Supporting your baby’s feeding mechanics, oral function, body tension, gut health and comfort helps reduce that strain. When feeding becomes more efficient and comfortable, babies are better able to use their energy for growth rather than just getting through feeds. We want our babies to thrive and not just survive!
If you’d like to gain a deeper understanding of tongue ties, including how they can impact not just milk feeds but oral function, breathing, sleep, and feeding development across the lifespan, my Tongue Tie Guide explores this in more detail in a calm, evidence-informed and parent-friendly way! Use the code insta60 to get 60% off the full price - for a limited time only!
And if you’re feeling unsure or would like personalised support, we’re always here to help, whether in person or virtually. Booking a consultation with us can be a gentle, supportive place to start.