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Why A Newborn Baby Tenses Up? (7 POSSIBLE REASONS!)

You may have noticed, and even be concerned, with your baby feeding, laying down, or interacting with you, only to suddenly tense their whole body up and almost go completely stiff. This often happens out of nowhere and for seemingly no reason, but could it mean that something is wrong?

Babies tensing up suddenly is quite common, and most of the time it is no cause for concern. It could be that they are having a stomach ache, teething pain or are overstimulated.

There are a few reasons why your baby might be tensing up, so read on to find out what these might be and how you might be able to help them.

What Does It Look Like When A Baby Tenses Up?

Why Does My Baby Tense Up? (6 POSSIBLE REASONS!)

Understanding how your baby might look when tensing or stiffening up will help you determine why they might be doing it, or if it is something more serious to worry about.

Here are some ways your baby might appear tense:

  • Your baby might make their whole body appear stiff and tense by almost straightening themselves out completely. They would be tensing the muscles in their arms and legs. Often this exertion leads to them making little noises as well. Their tensing should pass in a few seconds.
  • Your baby might tense up and harden their stomach. Usually, this means their little fists and legs tense up too.
  • Your baby might be stretching out their muscles and discovering more that they can do with their little bodies.

What Does It Mean When Your Baby Stiffens Up?

As your baby cannot tell you exactly what the problem is, it can be difficult to know why they are tensing up and if they are in pain.

However normal this might be for babies to stiffen their muscles, it can be concerning for parents to see.

If this is something you have noticed your baby doing before, here are some possible reasons it could be happening, and how you could try to help them.

Your Baby Is Constipated

One reason your baby might be tensing up is that they are constipated, or battling to pass a stool.

This can often lead to abdominal pain, which is why they would seem to be tensing up their stomach more than the rest of their body.

Constipation can be caused by a few different reasons, such as teasing or even a growth spurt.

There is not too much you can do to help them other than waiting for it to ease, but if your baby is unable to pass a stool for a day or so, it is best to phone your doctor and ask for advice.

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Your Baby Is Teething

Teething can be so painful for babies, and they really do not know how to deal with this sudden pain.

Not only can teething be painful, but it can be annoying and frustrating for babies too.

When we get frustrated and annoyed, we tense up, and the same is true for babies. They might also be tensing up from the sudden pain they feel from teething.

You will be able to tell that your baby is tensing up as a result of teething if they seem upset and irritable and if they display the other signs of teething such as drooling and trying to bite down on items.

There is not much that you can do to help with teething, but if you notice it is causing your baby quite a bit of pain and discomfort, you could give them teething gels and cold teething chews to help them.

Your Baby Has A Tummy Ache

Tummy aches come and go for many different reasons.

You might have given them a new food to try that didn’t sit too well, or they could have a stomach bug.

It is difficult to determine whether or not your baby is suffering from a tummy ache, but if they tense up their stomach and seem uncomfortable, it could be that they are having cramps.

Take note of your baby’s stools and their behavior and temperature.

If these are different and you can see that they are cramping and stiffening often, you should phone your doctor for advice.

Your Baby Is Overstimulated

Babies can become overstimulated quite easily.

Everything is new to them and they are still learning how to deal with the world around them. Surrounding them with too much noise, toys and lights can overwhelm them.

Your baby might become overstimulated if there is too much going on around them at one given time, and they might respond to this by becoming overwhelmed and frustrated, and tensing up.

To deal with this, remove your baby from the situation, whether it be their play mat or a crowded room, and help them calm back down again.

Your Baby Wants To Move Around

Even if your baby is still young, they might be excited to try out their body and get moving!

They might be tensing up to try and replicate standing or walking, even though they might not be ready to start yet.

They probably love their walker or bouncer and want to be put back in there.

If your little one tenses their legs and you think they might be wanting to stand or walk, hold them up safely and let them explore the feeling, or place them in their walker or bouncer for them to stand with some support.

Your Baby Has Reflux

Reflux is common in babies, and often if your baby is dealing with reflux, it could cause them to tense up.

You will be able to tell that their tensing is caused by reflux if they bring up milk soon after and seem uncomfortable and fussy.

Normal reflux now and then isn’t cause for concern, and with some help, your baby should manage through it, but if the reflux is more serious then you will need to phone your doctor for advice.

Your Baby Is Sulking

Although this would most likely not be your first thought, baby’s can absolutely sulk when they’re uncomfortable.

Since your baby has few ways of communicating their annoyances, they can simply sulk which manifests itself in stiffening out.

If your baby is in fact sulking, you can try moving them to another activity or place. Ignoring a sulking baby can lead to crying.

Is It Normal For Babies To Stiffen?

Why Do Newborn Baby's Tense Up - All about baby tensing up

It is normal for babies to stiffen up. They do not have the ability to respond to frustrations and problems the way that we do, and one way they might deal with this is by tensing up their body.

While you won’t be able to know exactly what is causing them to tense all the time, it could just be some discomfort such as tummy aches or teething.

However, if you notice your baby tensing up often and they seem upset or frustrated more than usual, you should call your doctor for advice.

Why Does My Baby Stiffen His Arms?

Noticing what area your baby stiffens can actually help you determine what the cause might be. 

For example, if your baby tenses up their stomach, it could be a sign that they are constipated or have a stomach ache.

If your baby tenses up their arms, it could simply be them stretching their muscles, or it could be that they are frustrated or overstimulated.

Your little one obviously won’t be able to communicate clearly with you, and they communicate the only way they know how, through their body and through cries.

Often if a baby tenses their arms, they are frustrated. Try to calm your little one down and remove them from a situation that could be causing them stress.

Why Does My Newborn Tense Up And Shake?

There are many reasons why your newborn might tense up and shake.

They might be stretching, they might be having a stomach cramp, reflux, or they might be feeling frustrated.

In order to try and figure out why your newborn is tensing up, you should take note of their behavior.

If they are fine before and after tensing up, then it is fairly safe to say that they are just exploring their body and all that it can do.

However, if they seem upset, frustrated, and uncomfortable, they might be having cramps, be constipated or be in pain.

Pay close attention to them after this to see if this goes away, and if not, phone your doctor.

It can be difficult to determine why your newborn is in pain or upset, and contacting your doctor is always the safest option.

What Should I Do When My Baby Tenses Up?

Most of the time, you should just leave your little one when they tense up.

You could gently stroke them and speak to them softly, but their tensing and stiffening up is usually over within a few seconds.

It is important to take notice if your little one is tensing up often and seems upset. If this is the case, then you will need to give your doctor a call.

While there is not much you can do when they are tensing, you can take this as a cue as something being wrong if it continues.

Other than this, babies tensing up and stiffening their arms and legs is fairly normal.

It is how they react to the world around them and any discomfort they are feeling.

It might seem a bit worrying at first, but it is usually nothing to stress about.

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