Low muscle tone (hypotonia) in babies and toddlers

Low muscle tone (also called hypotonia) is when your child's muscles feel softer and more relaxed than they should. If you relax your arm and pinch your muscle, the tension you feel is your muscle tone. Even when you are not using your muscles, they should have some tightness to them. Muscle tone keeps your body upright when you sit or stand.

If your child has low muscle tone, they may feel floppy when you hold them.

Muscle tone is not muscle strength. If your child has low muscle tone, this does not mean they are weak.

Low muscle tone is not a disease. It is usually a sign your child has an underlying health problem. Low muscle tone can affect your child's development.

If your newborn has low muscle tone, you might notice they:

• look floppy
• feel limp and can slide out of your arms when carrying them
• have a weak cry
• have a poor suckle
• cannot lift their head
• have poor reflexes
• have breathing problems

As your child gets older, you might notice:

• poor posture
• delays in reaching gross motor milestones — difficulty rolling, sitting, crawling or walking
• very flexible joints — they are comfortable sitting in positions that look painful
• drooling, poor chewing and speech difficulties if their mouth muscles are affected
• constipation
• they get tired very easily

Your child may have low muscle tone because of conditions affecting their muscles or nerves, including:

• hypoxic encephalopathy
• genetic disorders — Down syndrome, Prader-Willi syndrome, spinal muscular atrophy (SMA) or muscular dystrophy
• metabolic diseases
• endocrine problems
• infections
• congestive heart failure in newborns

Sometimes your child can have benign congenital hypotonia. This is when doctors do not know why they have low muscle tone.

If you are worried about your child's muscle tone, see your family doctor or maternal and child health nurse.

If your child's doctor suspects low muscle tone, they can diagnose it by:

• assessing their development
• asking about your family medical history
• doing a physical examination, and holding or moving your child in different positions to see their response

Usually, children are diagnosed at birth or shortly afterwards during routine newborn health checks.

Sometimes, your child can be diagnosed when they are a toddler when some developmental delays become obvious.

Once your child is diagnosed with low muscle tone, their doctor may recommend some tests to investigate what is causing it, such as:

• blood tests, urine tests and lumbar puncture
• genetic tests
• screening for metabolic diseases
• screening for infections — toxoplasmosis, rubella, cytomegalovirus (CMV) and HIV (human immunodeficiency virus)
• imaging — MRI (magnetic resonance imaging) or CT (computed tomography) scan

It is important to know why your baby has low muscle tone. This helps them get the right treatment. Diagnosing your child as early as possible is key for their development.

Read about development milestones — your child 12 to 18 months.
Read about development milestones — your child 18 to 24 months.

If your child has low muscle tone, their treatment will include therapies that suit their symptoms and development.

Therapies that can help your child:

• occcupational therapy to help with breathing, speech and swallowing difficulties
• physiotherapy to help with motor control and strength
• speech therapy to teach your child sign language until their speech improves
• nutrition support if your child is not eating well

If your child has weak ankle muscles, ankle and foot orthoses might help.

Ask your child's physiotherapist or occupational therapist to recommend activities to help their endurance. Here are some examples:

• Bouncing on a trampoline before sitting at a table helps your child sit up straight, instead of slumping.
• Playing with clay before drawing helps your child correctly grip their pencil.

If your child has benign congenital hypotonia, their muscle tone may gradually improve on its own.

Read about early childhood intervention.

It can be very overwhelming when your child has low muscle tone. You may worry about their future. Remember, you do not have to go through this alone. It is very important you look after yourself. Seek support from family, friends or community. Joining a local support group can also help.

If your child has low muscle tone, they may be at risk of:

• developmental delays
• not eating well
• respiratory infections

Depending on what is causing low muscle tone, your child can recover. For example, if an infection caused low muscle tone, when your child recovers, their muscle tone also improves.

Low muscle tone is usually a sign of a health condition you cannot prevent.

If a genetic condition has caused your child's low muscle tone, your doctor can refer you to a genetic counsellor. They may recommend you do genetic tests to check your risks of having another child with the same condition. They can guide you through your options.

• Read more about low muscle tone at the Royal Children's Hospital Melbourne's website.
• MyTime supports parents and carers of children with disabilities by offering support groups.
• For advice and to get connected to local mental health services, call Medicare Mental Health on 1800 595 212.

Do you prefer to read in languages other than English?

The ACD - Advocating for children with disability is a service for children with disabilities and its website is translated into many languages.

Looking for information for Aboriginal and/or Torres Strait Islander people?

• Visit Birthing on Country for information on projects that support Aboriginal and/or Torres Strait Islander babies and their families.
• Visit Emerging Minds, an organisation that supports Aboriginal and Torres Strait Islander families and children living with disability.