Spinal muscular atrophy in infants Spinal muscular atrophy (SMA) symptoms
Signs of SMA

All babies develop differently, but developmental delays and other symptoms can be signs of spinal muscular atrophy (SMA), a rare genetic disease which requires urgent medical attention. To ensure your baby’s progress is on track, it’s important to know what to look out for

HOW TO SPOT THE EARLY SIGNS OF SMA

Select age range:

Early signs of SMA are typically seen any time before 3 months, or up to 6 months of age. If you feel something isn’t right with your baby, or your baby is displaying any of the following early signs of SMA, trust your instincts and speak to your doctor

Poor Head Control

  • When your baby is lying on their back, their head may rest on one side with little movement, they might struggle to move it from side-to-side, and to lift their head up
  • When holding your baby, they may struggle to lift their head up or to move it from side-to-side, even for a short period of time
  • When your baby is lying on their tummy they may have difficulties lifting their head up and moving it from side-to-side
  • Watch the video to see how your doctor will check for head control

Weak Legs & Arms

  • When lying on their back, your baby may not move their arms and legs very much, rarely kicking their legs or moving their arms away from their body. They might struggle to lift their arms and legs up, struggle to reach for things, and their legs may be in a ‘frog leg’ position
  • Your baby’s arms and legs may seem weak and lacking strength, they may appear floppy, particularly their legs, or feel limp when held

Fast Belly Breathing

  • Your baby’s breathing may be fast, even when they are resting and they do not seem to take deep breaths in or out
  • Their chest may appear ‘bell-shaped’. When breathing, their belly may move up and down noticeably more than their chest – this can most easily be seen when they are lying on their back and are not wearing clothes on the upper half of their body

Difficulty Feeding/Swallowing

  • Your baby may struggle to suck or swallow when feeding due to weakness. This can lead to choking and make it harder for them to gain weight
  • You may notice they are slow when feeding as they struggle to swallow
Baby 0-6 months difficulty feeding and swallowing early sign of Spinal Muscular Atrophy (SMA)

Weak CRY & COUGH

  • Your baby’s cry might be difficult to hear and seem weak
  • They may also struggle to cough and clear mucus from their chest; their cough may sound weak and they may cough repeatedly and sound ‘chesty’

Remember, even babies with SMA remain alert, responsive and smiley. They’ll appear happy, not in distress, which makes it less obvious that there might be a problem. But if you feel something’s wrong, don’t hesitate to see your doctor

Early signs of SMA are typically seen any time before 10 months, and up to 18 months of age. If you feel something isn’t right with your baby, or your baby is displaying any of the following early signs of SMA, trust your instincts and speak to your doctor

Weak Legs & Arms

  • Your baby’s arms and legs may seem floppy and like they lack strength. This is usually more noticeable in the legs
  • They may be unable to push up to their elbows and hold this position for long periods when lying on their tummy
  • Your baby may struggle to reach out and grab or pick up toys; when performing these movements they may seem slow and tire easily
  • They may struggle to support themselves using their legs when held

Struggles to Sit Unsupported

  • When placed sitting upright, your baby might struggle to stay still for long and may lean forward or to one side; at first, this lean may be only slight
  • Your baby may find sitting increasingly difficult and need further help to maintain the position for long periods

Can’t Roll Over

  • Your baby might rock from side-to-side but struggle to roll fully onto their side; or they may find it difficult to roll onto their tummy when lying on their back
  • Over time, they may find these movements increasingly difficult

Shaking Hands

  • Look out for small tremors or shakes in the fingers or hands when your baby holds their arms out. This shaking may be minor and difficult to see clearly
Baby 6-18 months has shaking hands early symptoms of spinal muscular atrophy (SMA)

Slow/Lost Physical Development

  • They may be slow to achieve different developmental milestones such as sitting or standing without support or walking
  • They may manage to reach these milestones but later become unable to do so
Baby 6-18 months slow or lost physical development early symptoms of  spinal muscular atrophy (SMA)

Remember, even babies with SMA remain alert, responsive and smiley. They’ll appear happy, not in distress, which makes it less obvious that there might be a problem. But if you feel something’s wrong, don’t hesitate to see your doctor

Age 0-6 months Age 0-6 months
Age 6–18 months Age 6–18 months

Understanding more about YOUR BABY’s progress

Alongside the key signs of SMA, your baby’s movement and development can sometimes suggest that something isn’t quite right. Tracking your baby’s movements, also known as motor (or developmental) milestones, in the first few months of life is very important in helping you to see how well they’re developing

Alongside the key signs of SMA, your baby’s movement and development can sometimes suggest that something isn’t quite right. Tracking your baby’s movements, also known as motor (or developmental) milestones, in the early months of life is very important in helping you to see how well they’re developing

Milestones are a measure of the physical progress your baby makes as they grow. Seeing your baby grow and develop is a fascinating experience – from birth onwards you will have plenty of exciting ‘firsts’ to look forward to

This figure illustrates typical development patterns in the first few months of life, so you can see how your baby is progressing. Every baby is unique, the exact age individual babies show these skills may differ

1 month old

  • 1 month old development milestone baby can lift head when laying on their front

    When lying on their front, baby can briefly lift their head

  • 1 month old development milestone  old baby can move hands to their face and mouth

    Can move hands to their face and mouth

  • 1 month old development milestone old baby can startle reflex

    Startle reflex – when baby is startled, such as a loud noise, they throw out their arms and spread their fingers

2 months old

  • 2 month old development milestone baby can lift head while laying on their front

    When lying on their front, baby can lift their head and move it side-to-side – may also use arms to push off of the ground

  • 2 month old development milestone baby can move and wiggle their arms and legs when laying on their back

    When lying on their back, baby can move and wriggle their arms and legs. As development continues these movements will become smoother

  • 2 month old development milestone baby can briefly hold toy

    Can briefly hold a toy that is placed in their hands

3 months old

  • 3 month old development milestone baby can lift their head and chest when laying on their front

    When lying on their front, baby can lift their head and chest

  • 3 month old development milestone baby can wave their arms and kick their legs when laying on their back

    When lying on their back, baby waves their arms and kicks their legs

  • 3 month old development milestone baby can begin to reach out for toys and grasp and hold items

    Beginning to reach out for toys and deliberately grasps and holds items

4 months old

  • 4 month old development milestone  baby can hold their head straight and look around when on their front

    When lying on their tummy they can hold their head straight and look around

  • 4 month old development milestone baby can rock side to side when laying on their back

    When lying on their back they rock from side-to-side

  • 4 month old development milestone baby can push up to their elbows when laying on their front

    Pushes up to elbows when lying on their tummy

  • 4 month old development milestone baby can grab and shake toys in their hands

    They grab and shake toys in their hands

6 months old

  • 6 month old development milestone baby can begin to sit up

    Beginning to sit up without help

  • 6 month old development milestone baby can roll from side to side and over to their front

    Rolls from side-to-side and rolls over front-to-back

  • 6 month old development milestone baby can support their own weight on their legs and stand with help

    Beginning to support their weight on their legs and stand with help

  • 6 month old development milestone baby can start to crawl

    Starts to crawl on their hands and knees

6 months old

  • 6 month old development milestone baby can begin to sit up without help

    Beginning to sit up without help

  • 6 month old development milestone baby can roll from side to side and roll over front to back

    Rolls from side-to-side and rolls over front-to-back

  • 6 month old development milestone baby can begin to support their weight on their legs and stand with help

    Beginning to support their weight on their legs and stand with help

  • 6 month old development milestone can crawl on their hands and knees

    Starts to crawl on their hands and knees

9 months old

  • 9 month old development milestone can crawl on their hands and knees

    Crawls on their hands and knees

  • 9 month old  development milestone baby can pull themselves up to stand

    Can pull themselves up to stand whilst holding onto something

  • 9 month old development milestone baby can stand whilst holding onto

    Can stand whilst holding on to something

  • 9 month old development milestone can begin to take a few steps whilst holding onto furniture for support

    Beginning to take a few steps whilst holding onto furniture for support

12 months old

  • 12 month old development milestone can stand alone without help

    Can stand alone without help

  • 12 month old development milestone  can begin to take a few steps

    Begins to take a few steps alone

  • 12 month old development milestone can get into the sitting position alone and sit well

    Can get into the sitting position alone and sits well

18 months old

  • 18 month old development milestone can walk well alone

    Can walk well alone

  • 18 month old development milestone can start to walk upstairs and run

    Starts to walk upstairs and run

  • 18 month old development milestone can begin to feed themselves with a spoon and drink from a cup

    Beginning to feed themselves with a spoon, and drink with a cup

If you notice your baby hasn’t reached any of these milestones within the expected age range, or they are no longer able to achieve milestones that they previously could, speak to your doctor immediately

Download the milestones timeline

MILESTONES TIMELINE

References

References

Cambridgeshire Community Services NHS Trust. Child Development milestones. Available at: https://www.cambscommunityservices.nhs.uk/advice/childhood-development/milestones Date accessed: October 2020.

Chabanon A, et al. PLoS One. 2018;13(7). doi: 10.1371/journal.pone.0201004.

Edwards CW and Al Khalili Y. Stat Pearls. 2020 Jan [Updated 2020 Aug]. Available at: https://www.ncbi.nlm.nih.gov/books/NBK542173/. Date accessed: October 2020.

Glascock J, et al. J Neuromuscul Dis. 2018;5(2):145–58.

Govoni A, et al. Mol Neurobiol. 2018;55(8):6307–18.

Healthy children. Physical Developmental Delays: What to look for. Available at: https://www.healthychildren.org/English/MotorDelay/Pages/default.aspx#/activity/0to7months. Date accessed: October 2020.

Help me grow MM. Motor Developmental Milestones. Available at: https://helpmegrowmn.org/HMG/DevelopMilestone/MotorMilestones/index.html Date accessed: October 2020.

Kolb SJ and Kissel JT. Neurol Clin. 2015;33(4):831–46.

LoMauro A, et al. PLoS One. 2016;11(11):e0165818. doi: 10.1371/journal.pone.0165818.

Pera MC, et al. PLoS One. 2020;15(3). doi: 10.1371/journal.pone.0230677.

NHS (2018). Hypotonia. Available at: https://www.nhs.uk/conditions/hypotonia/. Date accessed: October 2020.

Prior TW, et al. Spinal Muscular Atrophy. 2000 Feb 24 [Updated 2019 Nov 14]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020.

Qian Y, et al. BMC Neurology. 2015;15:217.

SMA Europe (2020). Type 1. Available at: https://www.sma-europe.eu/essentials/spinal-muscular-atrophy-sma/type-1/. Date accessed: October 2020.

SMA Europe (2020). Type 2. Available at: https://www.sma-europe.eu/essentials/spinal-muscular-atrophy-sma/type-2/. Date accessed: October 2020.

Verhaart IEC, et al. Orphanet J Rare Dis. 2017;12:124.

Wang CH, et al. J Child Neurol. 2007;22(8):1027–49.

WHO Multicentre Growth Reference Study Group. Acta Paediatr Suppl. 2006;450:86–95.