Hypertonic baby: a guide for parents

Babbling, cries, smiles… Even though your baby hasn’t mastered language yet, they certainly have many ways to communicate with you. Did you know that even their muscle tone plays a part in this communication? Yes—this is precisely what we refer to as hypertonia. What is it? How can you tell whether your baby’s tone is normal? When should you consult a doctor?

Hypertonic baby: here’s what you need to know.

What Is Hypertonia and How Is It Characterized in Babies?

Hypertonia is a normal characteristic in newborns. It refers to the stiffness of their limbs. Right after birth, an infant’s limbs are curled up tightly against their body and contracted: they are “hypertonic” (which surely makes dressing them a bit tricky). Conversely, they cannot yet hold up their head or back—they feel “floppy.” This is what we call hypotonia in the trunk.

A little later, starting around 3–4 months, when muscle tone becomes regulated and movements become intentional, this tone helps them express themselves… In fact, as psychologist Henri Wallon noted back in 1930, babies alternate between phases of “calling hypertonia (muscle tension)” and “satisfaction hypotonia (muscle relaxation)”. Your baby then uses their whole body to communicate with you.

At that point, the trunk and neck strengthen, reducing the tone in their limbs (leaving that hypertonic state). This allows them to develop fine motor skills and grasping abilities: that is, skill, precision, and the ability to hold objects.

Hypertonia in a newborn is therefore normal. However, when it persists over time, hypertonia may be a symptom of a condition or disorder. In that case, we speak of pathological hypertonia.

It’s also possible that prolonged hypertonia is simply temporary rather than pathological—a fairly common phenomenon. A healthcare professional will be able to determine whether the hypertonia is pathological or merely temporary.

When Should You Consult a Specialist About a Baby’s Hypertonia?

Hypertonia is very common in infants, but it is not supposed to last too long. Otherwise, it may be pathological hypertonia.

As a guideline, limb hypertonia at birth tends to diminish around 8 months. Stiffness gradually gives way to greater flexibility: this allows your baby to gain mobility, discover body support, and explore all their abilities. Later on, their legs will strengthen again to help them stand and walk.

As always, if you have any doubts or questions about your baby’s health, don’t hesitate to consult their doctor.

What Are the Common Causes of Hypertonia in Infants?

When hypertonia is pathological, it is a sign of a muscle tone disorder in the baby. This pathological hypertonia may stem from various physiological conditions (genetic disease, intrauterine infection, peri- or postnatal infection…). In such cases, we speak of:

• Spastic hypertonia: the limbs and muscles remain tense at all times, even at rest. This is a physiological phenomenon.
• Hypertonia related to the “cogwheel phenomenon”: muscle tension increases significantly and then releases in jerks. This is also a physiological phenomenon.

Does Hypertonia Affect a Baby’s Overall Development?

As mentioned earlier, under normal conditions, a newborn’s hypertonia gradually decreases to allow them to acquire motor skills such as grasping and fine motor movements. When muscle tone does not regulate normally, the child is unable to acquire these new skills. When it is pathological, hypertonia can indeed affect a baby’s overall development.

However, pathological hypertonia is generally a symptom of an underlying condition that causes tone disorders. It is therefore not the hypertonia itself that causes developmental delays, but rather the underlying disorder or disability.

❕Before discussing developmental disorders, these must first be diagnosed by a healthcare professional. Don’t worry if your baby doesn’t roll over at the same age as another child—every baby develops at their own pace.

Want to learn more? Feel free to download the May app, where you’ll find plenty of resources to support and guide you throughout your journey as a new parent.

How Can Parents Support Their Hypertonic Baby Daily?

My baby has been diagnosed with hypertonia: what can I do? How can I improve their daily comfort? What care can I provide at home? Sarah Lachot, psychomotrician, shares her advice:

“When a baby presents hypertonia, they tend to stay extended with bodily tension. These babies may have difficulty curling in and regrouping to relax. Curling movements are essential to reduce body tension and promote muscle relaxation.

Here are some passive curling techniques:

• While lying on their back, bring the baby’s feet toward their face by lifting the pelvis to help them curl in.
• From a lying position on their back, gently roll the baby onto their side so they can regroup laterally.
• While lying on their back, bend one leg toward the chest, then extend it while bending the other. Alternate these flexion/extension movements several times to stretch the muscles.

An idea for active curling:

• Encourage your baby to grab their feet to curl their pelvis and bring their arms forward.

For everyday care:

• Favor ergonomic babywearing using a wrap or baby carrier.
• When holding your baby, carry them in a “little Buddha” position.
• Offer gentle massages.

If in doubt, don’t hesitate to talk to your pediatrician, who may refer you to a psychomotor therapist or a pediatric physical therapist if needed.”

Hypertonia refers to the stiffness of the limbs—in this case, a baby’s limbs. It is a typical characteristic of newborns. However, there is also a pathological form of hypertonia. If you are concerned, don’t hesitate to consult a healthcare professional.

Photo: DragonImages

This text was translated from French by an artificial intelligence. The information, advice, and sources it contains comply with French standards and may therefore not apply to your situation. Make sure to complement this reading by visiting the May US/UK app and consulting the healthcare professionals who are supporting you.