Baby Stiffens Legs When Changing Diaper | Any Reason for Concern?

| Reviewed By Amanda Lundberg, BSN, RN

Have you ever noticed your baby going unusually stiff at random times? Sometimes this happens during the most inconvenient times, such as during diaper changes or when you are trying to put them in their car seat.

For new parents, this may cause you to worry slightly. Is this normal?

Why does my baby stiffen legs during diaper changes? When a baby stiffens their legs, it is not usually a reason for concern. This is a very normal thing for babies to do as they are discovering new muscles and learning new ways to react to the world around them and communicate frustration or pain. 

In the following, we will discuss more about why babies tend to stiffen up during diaper changes and on other occasions.

We will talk about what parents can expect from their babies and dive deeper into warning signs and reasons for concern when it comes to babies stiffening their muscles. 

Stiff Legs During Diaper Changes

We’ve all been there. That frustrating moment when you are trying to change your baby’s dirty diaper and they seem to be stiff as a board, making it nearly impossible to get them clean.

A stiff baby may cause a new parent to worry. Before you call your pediatrician, let’s learn a little bit more about what is normal and why babies tend to stiffen up during diaper changes. 

Why Babies Stiffen Legs During Diaper Changes

One of the primary reasons that babies stiffen their legs during diaper changes is because it is a frustrating time for them and not always the most comfortable.

Their legs get cold, they don’t like having their legs picked up, and they anticipate the coldness of the baby wipe.

As a reaction to this discomfort and in an effort to communicate their frustration, babies will often stiffen their legs when undergoing a diaper change. 

Should You Be Worried? 

As mentioned, stiffening of the legs during diaper changes is a very common and normal thing that babies do. It is simply one of their means of communicating frustration, pain, or discomfort. It is not usually a cause for concern. 

However, if the stiffness exceeds temporary moments of pain or frustration and begins to hinder your baby’s ability to move, then it may be time to see a professional. 

Other Ways Babies Make Diaper Changes Difficult

Stiff legs are not the only frustrating thing that babies do during diaper changes.

Once babies become more mobile and develop a greater sense of independence, diaper changes become even more dreadful for them as it temporarily limits their ability to move around and be independent.

They express this frustration in other ways such as: 

  • Twisting, turning, or rolling
  • Kicking
  • Crying and fussing

How To Make Diaper Changes Easier

If diaper changes are getting progressively more difficult, there may be some things you can do to make it a bit more enjoyable. Try a few of these tips: 

  • Sing to your baby.
  • Give your baby a toy to play with.
  • Make noises and play with your baby while you change their diaper. Blow tummy raspberries, tickle, and play. 
  • Have the clean diaper ready to go under the dirty one in order to make the change quick and seamless.

Other Times Your Baby May Stiffen Legs and Arms

You may notice your baby stiffening their arms and legs at other times besides diaper changes. It is common for babies to stiffen when they are frustrated about something, uncomfortable, or in pain.

Teething, being put into the car seat, or not being able to do something they want to do are examples of such instances.

However, the opposite is also true, and they may stiffen when they are excited, such as when they are being picked up or see something that makes them happy. 

Baby Stiffens Legs and Arms and Grunts

Grunting is a very common thing that babies do for a variety of reasons. It is often paired with stiffening of the legs and arms as well.

Again, it is not usually a cause for concern. Most often, babies will grunt and stiffen their arms and legs in the following instances:

  • Trying to pass stool.
  • Reflux or GERD, particularly in newborns.
  • Situations where they are frustrated about something (diaper changes, being put in the car seat, etc.).
  • Excitement or to yield a reaction from others.

In most cases, a baby grunting should not be extremely alarming. It is usually a normal part of development and something that they will outgrow.

However, if you notice that your baby’s grunts seem to be accompanied by a lot of pain or something really doesn’t seem right, always reach out to a medical professional. 

Baby Stiffens Body and Cries 

Crying is a completely healthy and normal behavior for babies. Particularly in the first several months to the first year of their lives, crying is a baby’s way of communicating their needs to their parents.

A newborn infant will often cry because they are experiencing mild pain. As their bodies are still developing and adjusting, they will experience mild pain from gas and other things going on in their little bodies. 

In a small number of cases, crying accompanied by stiffening and an arched back is a sign of more serious problems such as spastic cerebral palsy or other birth injuries. However, this is very rare.

It is most likely that your baby is experiencing pain from something, and you should seek medical attention, but you should not worry too much about it being something as significant as cerebral palsy.

If you are concerned that your baby does have a birth injury, read on, and we will discuss them in greater depth. 

A newborn baby dressed in white lying down and screaming.

Baby Stiffens Body When Picked Up

Most of the time, a baby will stiffen while being picked up out of anticipation and excitement.

Researchers have found that a newborn baby can sense when their mother is about to pick them up and will stiffen in preparation. In most cases, this is normal behavior. 

Hypertonia in Babies

Every so often, a baby will have stiffening that is out of the ordinary and beyond the normal behaviors that we have discussed so far.

If you have noticed that your baby is unusually stiff, so much that it impedes their ability to move around, or if your baby’s muscles feel tight to the touch, you will want to seek medical attention to determine if your baby has a condition called hypertonia. 

Hypertonia Explained

When we move our limbs, our muscles contract and relax. Muscle tone is the amount of tension, or resistance to movement, in our muscles. 

Hypertonia is when a baby’s muscle tone is too high. Because of this, their muscles are constantly contracting, remaining tight, and resisting movement.

Basically, when a baby has hypertonia, they are unable to relax their muscles and they remain in a state of contraction. 

Hypertonia can be congenital, or it could be the result of a brain or spinal cord injury, usually during birth. It is usually diagnosed before the age of two. 

Hypertonia Symptoms

Hypertonia causes babies to move differently due to a limited range of motion in the joints. This can make the symptoms easy to spot because your baby’s movements will not look normal.

If you are concerned about hypertonia, look for the following symptoms: 

  • Difficulty moving arm, leg, and neck muscles. 
  • Robotic movements because of limited motion in the joints and an inability to relax muscles.
  • Poor balance and falling.
  • Limited joint movement and flexibility.
  • Involuntary muscle twitching or jerking.

Mild Hypertonia in Babies

There are a few different types of hypertonia that will affect babies differently and have different outcomes. 

Spasticity describes a type of hypertonia that is characterized by muscle spasms and exaggerated reflexes during movement.

Rigidity is hypertonia that is characterized by stiffness even without movement. In these cases, babies are always unusually stiff. 

The severity of hypertonia can also vary. Some babies may have very mild hypertonia characterized by moderate stiffness and difficulty moving as other babies do. Mild hypertonia often improves over time and with treatment. 

Hypertonia Treatment

If detected early enough, hypertonia can often be treated. Mild cases of hypertonia are often treated with physical therapy and stretching exercises. Massages, joint compressions, and practicing normal movements are also common parts of treatment. 

Sometimes, casting a muscle is necessary in order to stretch it out for a period of time and create a greater range of motion. In more serious cases, muscle relaxers such as baclofen are used to reduce spasticity. 

Is Hypertonia the Same as Stiff Baby Syndrome?

Hypertonia is different from Stiff Baby Syndrome. Stiff Baby Syndrome is a genetic disorder known as hyperekplexia in which babies have an exaggerated startle reflex.

Babies with this disorder will have extreme reactions to loud noises and unexpected movements or touches. These reactions can range from eye blinking and spastic jerking movements to falling stiffly to the ground. 

Hypertonia and Stiff Baby Syndrome are often confused because both involve rigidness and stiffness in babies. However, they are different, and hypertonia is often a byproduct of Stiff Baby Syndrome. 

Can Hypertonia Be Cured? 

Hypertonia is a lifelong condition; however, depending on the severity, it can improve over time with treatment.

The treatment aims to reduce symptoms and improve muscle function. The timeline or extent of symptoms improving depends on the severity and cause of the diagnosis. 

Signs of Cerebral Palsy in Children

The main symptoms of cerebral palsy are problems with movement, coordination, and development. 

Possible signs may include: 

  • Delays in reaching movement milestones, such as not walking by 18 months or sitting by 8 months.
  • Walking on tiptoes.
  • Seeming too stiff.
  • Weak arms or legs.
  • Random, uncontrolled movements.

If your child is not reaching their milestones or exhibiting any of these symptoms, it is important to consult their pediatrician. 

Related Questions:

Should You Lift Baby’s Legs To Change Diapers? 

The typical, double leg lift to change a baby’s diaper can actually put a lot of stress on their lower back and contribute to digestive issues.

Baby and toddler developmental specialists say that the best thing you can do is roll your baby from side to side during diaper changes to protect their spine.

Can Diapers Affect Baby Walking?

Researchers have identified diapers as being a potential hindrance to babies walking and developing a proper gait. If anything, diapers may delay your baby’s ability to walk by a few months.

However, they are not going to keep your baby from learning to walk properly. It is really up to you to decide if your baby walking sooner is worth enough to power through getting on your hands and knees to clean up accidents all day long.  

Final Thoughts

It is our job as parents to protect and help our children. This inevitably causes us to worry… sometimes a little too much!

Hopefully, you have gained a little bit more insight into why your baby may be acting a little stiff sometimes and have received some comfort or, if necessary, guidance on what steps to take next to help your little one.