Have you ever seen a baby pull her feet up close to her face? Most adults wouldn’t even think of attempting a stunt like that. But babies do it all the time. They’re very flexible! However, hypertonic infants, or a baby with stiff baby syndrome, can’t do this adorable trick.
When is a stiff baby a cause for concern? A little stiffness may be no big deal. But sometimes, the underlying cause of stiffness is a birth injury. In that case, the situation may be serious. Read on for more about hypertonic infants and how medical malpractice can lead to stiff baby syndrome.

What Is Stiff Baby Syndrome?
If you pick up a healthy baby, he might stiffen his legs and arms out of excitement. This isn’t anything to worry about. It’s also normal for babies to tighten up their bodies when they get frustrated. They might do this when they don’t want you to put them in a car seat or highchair.
But there’s another type of stiffening that is cause for concern. When a baby’s muscles are always stiff, it can be a sign of an underlying illness. This condition is called hypertonia, or stiff baby syndrome. Hypertonic infants can appear almost statue-like. They might not be able to raise their arms over their heads, or rotate their torsos with ease.
There are two types of hypertonia:
- Dystonic hypertonia: The baby is stiff all the time. His muscles never (or rarely) relax.
- Spastic hypertonia: The baby’s muscles tighten often, such as when being picked up.
The muscle stiffness in hypertonic infants can range from mild to severe. Sometimes, it goes away on its own and isn’t a cause for concern. Other times, hypertonia has a specific cause. It can stem from birth trauma, or be a sign of a hidden condition.
What Are The Symptoms Of Hypertonia?
Like we mentioned before, hypertonic babies are stiff. And that’s because they have too much muscle tone. Now the symptoms vary a good bit, both in type and severity.
Here are a number of those symptoms:
- Troubles moving neck, legs, or arms
- Limited range of motion
- Limited flexibility
- Limited joint movement
- Soreness and/or throbbing muscle pain
- Falling frequently, lack of balance
- Joints freezing in place
- Muscles, skin, tendons etc tightening permanently (contracture)
- Twitching or jerking muscles (myoclonus)
Now that we’ve covered the symptoms, let’s cover what causes hypertonia to begin with?
What Causes a Stiff Baby?
Most of the time, hypertonia is a brain and nerve issue. When you want to move, your brain sends a signal to your muscles. The muscles contract or relax. In hypertonic infants, something interferes with this signal. Usually, it’s an injury to the brain or spinal cord. The injury may occur while the baby was in the womb, during the birth, or after. Here are some examples of conditions that can cause hypertonia. We’ve included a brief explanation of how they can lead to hypertonia and a stiff baby.
- Cerebral Palsy. This medical condition develops when blood flow to a baby’s brain is reduced or cut off during birth. This causes an oxygen shortage. The lack of oxygen damages the part of the brain that controls muscle movement.
- Strokes. Neonatal strokes can occur when a baby doesn’t get enough oxygen while traveling through the birth canal.
- Head trauma. A head injury, such as one inflicted by forceps during delivery, can damage the brain and cause hypertonia.
- Brain tumors. Tumors are abnormal cell growths. They may affect the part of the brain that controls movement, causing a stiff baby.
- Exposure to a harmful chemical. If a baby comes into contact with a chemical that damages the brain, she may develop hypertonia.
- Kernicterus. Some babies get jaundice after birth. Bilirubin, a waste product from the liver, builds up and turns the skin yellow. If jaundice goes untreated, it can become kernicterus. Kernicterus is a serious condition that often leads to brain injury.
- Erb’s Palsy and shoulder dystocia. A baby can get stuck while coming down the birth canal. Doctors may pull too hard on the baby’s neck or shoulder in order to speed the process along, or use a vacuum or forceps. Shoulder dystocia is the name for the damage to a baby’s neck or shoulder nerves. This damage can lead to Erb’s palsy. Muscle stiffness is a symptom of Erb’s Palsy.

Hypertonic Infants & Birth Injuries
You might have noticed that many of the possible causes for a stiff baby stem from birth injuries. For example, if a doctor pulls too hard on a baby’s shoulder while delivering her, she can develop shoulder dystocia and become hypertonic. The same goes for exposure to chemicals, or leaving jaundice untreated.
Another example is when a mother struggles to give birth. The baby is in danger of oxygen deprivation. The situation requires a cesarean section. But the doctor in charge doesn’t order one in time, or at all. The baby develops Cerebral Palsy and subsequent hypertonia.
This would be an example of medical malpractice. Why? Because the physician didn’t follow the standard of care for that situation. The parents of the hypertonic infant may be able to sue the doctor for negligence. In fact, Cerebral Palsy is one of the most common conditions involved in birth injury lawsuits.
Are you a parent of a hypertonic infant? Has a doctor’s mistake led to a stiff baby or another devastating birth injury? Speak with our caring, compassionate birth injury lawyers today. We’re on your side! Contact us here.
Hypertonic Infants & Stiff Baby Syndrome FAQs
What is a hypertonic infant?
Hypertonia is a condition where a newborn baby has an excessive amount of muscle tone and stiffness. So hypertonic infants have too much muscle tone, and that causes stiffness.
Is a stiff baby cause for concern?
A stiff baby can be a cause for concern, because it may indicate a health issue that requires medical attention.
What causes hypertonia in an infant?
Hypertonia can be caused by various factors such as brain injury, metabolic disorders, and genetic conditions. Sometimes, the cause is medical malpractice. Example: The doctor negligently fails to order a c-section in a timely manner, and the baby’s brain is injured, causing hypertonia.
What are the symptoms of hypertonia?
The symptoms a hypertonic infant may display include excessive muscle tone, stiffness, myoclonus (jerking or twitching muscles) and difficulty moving.
How are hypertonic infants diagnosed?
They’re diagnosed through physical examination and tests like CT scans, electromyograms and MRIs.
Will a hypertonic infant have long-term health issues?
Hypertonia can lead to long-term health issues, like delays in developmental and mental disabilities, if not treated properly.











