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Spinal Muscular Atrophy

As parents and/or caregivers of a baby, you will watch your baby learn and grow through their early years. Being aware of the milestones babies should reach is key and can help you notice any changes or delayed development.

In rare cases, developmental delays can be an early sign of spinal muscular atrophy (SMA), a devastating disease that causes weakness and muscle wasting. This article highlights the early signs and symptoms of SMA and what to do if you're concerned about your little one

Understanding delayed baby development and missed milestones

Watching your baby develop and grow is one of the many great joys of parenthood. Each time your baby learns a new skill, they are meeting a developmental (or motor) milestone - a measure of the physical progress your baby makes as they grow. Although every baby is unique and timings may vary slightly, there are key milestones in the first few months that they should generally reach.

1 month old

2 months old

3 months old

4 months old

6 months old

9 months old

12 months old

18 months old

If you notice any delays in your baby's development, it may be nothing to worry about. It is common to see some variation in the age that babies achieve the milestones listed above, even in healthy children.

However, if you are concerned, it's important to speak to your family doctor or health visitor. In rare cases, developmental delays or other signs such as those listed below can be signs of neuromuscular diseases (NMDs) such as SMA. SMA is a rare, genetic condition that progresses quickly and requires urgent medical attention.

About SMA

SMA is a rare, devastating, genetic disease that leads to weakness and wasting in muscles used for movement. It predominantly affects around one in 10,000 - 12,000 live births and can impact any race or sex. With SMA, nerves are lost, causing weakness of the muscles. This happens when special nerve cells in the body that control muscle movement, called motor neurones, deteriorate and stop working. SMA progresses quickly, so it's important to seek medical advice urgently.

See Signs of SMA website for more information.

What should I do if I'm concerned?

The more information you can give the doctor about the signs you have noticed and the concerns you have about your baby's development, the better equipped they'll be to provide the best advice.
Visit Signs of SMA website for more information on:

  • More detail on developmental milestones.
  • More information on the early signs of SMA.
  • Access to a useful personalised discussion guide that can help prepare for conversations with your doctor.

For more detailed information on the developmental milestones and the signs of SMA (including video examples), please visit the Signs of SMA website.


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ALL-UNB-20-0177 Date of preparation: December 2022

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