Growth and development after prematurity

Premature birth can affect the way your child develops. Assessments from your healthcare team are crucial in ensuring that your baby gets the right care.

Watching your child develop can be one of the most fascinating aspects of parenthood. As your baby's brain and body grow and their pathways gradually connect up, babies learn to smile, then crawl, walk, speak - and develop many other skills along the way. If you're concerned that your baby may have health problems, the excitement you feel as you watch them develop may be mixed with worry.

Factors influencing your child's development

Premature birth can affect the way your child develops, and the earlier your child was born, the higher the risks, so you need to keep an eye out for any area where you think there could be a delay. However, it's all about striking a balance: every child develops in their own unique way.

Your baby's development will depend on a range of factors, including:

  • genetic make-up
  • the environment
  • influences around him. 

Development milestones are based on averages. Not meeting given milestones is not just an issue for pre-term babies. Term babies sometimes do not meet development milestones either.

How their time in hospital can affect premature babies

There can be some delays in the development of motor skills among premature babies, partly due to treatments when they are small, such as being on a ventilator, although growing awareness of positioning techniques is helping to reduce this.

If a baby's experiences in the unit prevents them from developing appropriate muscle tone, this can have a knock-on effect. For example, if they achieve sitting later than expected, this in turn can delay subsequent skills, such as hand function.

Delays appear to be becoming less common among babies with a birthweight of 1 to 1.5kg.

Prematurity and growth

Premature babies start small, and although they do tend to catch up as they get older, children born very prematurely still tend to be smaller and lighter than their classmates. However, as our knowledge of nutrition continues to develop, and with extra supplements available to support premature babies' dietary needs, this may change.

As premature babies develop through childhood and adulthood, it becomes harder to know which of their traits and characteristics are a result of premature birth rather than other factors.

As your child was born prematurely, they will be considered in a high risk group for developmental problems and they are likely to have more assessments of their progress than a term baby would. This is routine, not because there is something wrong or there will be something wrong but because early detection and diagnosis of any potential problems are key to prevention.

Many low-birthweight babies and their families are invited to attend follow-up or neurodevelopmental clinics so that the healthcare team can assess the baby's progress and intervene early where treatment is needed.

Where possible specialty services will be co-ordinated so that you do not have to attend many appointments. Follow-up visits will also be scheduled during the first years of their life.

As well as looking at how your baby is developing, the healthcare team will regularly check their weight, head circumference and height (also known as length) to make sure they is growing as expected.

Understanding your baby's growth chart

You will be given a Personal Child Health Record, or 'red book', which has growth charts to help plot your baby's growth and compare it with the average growth for their age. Babies born at less than 32 weeks are plotted in the low-birthweight chart. Babies born at 32-37 weeks are plotted in the preterm chart until two weeks after their estimated due date and from then on are plotted in the main charts, but with their gestationally corrected age.

How centile charts work

Babies' progress is described in measurements that are called centiles because they relate to average percentages. The curves on the chart show the usual progression for a baby, as a baby's weight will normally increase and level off at certain ages. So, for example, if your baby's height is in the fifth centile for their age, that means that if you lined up 100 children in order of height, your child would be at number five, with a child at the 100th centile being the tallest. There are separate charts for girls and boys, as boys tend to be heavier.

The centiles for weight and height should usually be similar - if they are very different from each other, this may indicate that your baby is overweight or underweight, and your team may need to adjust the feeding regime.

Developmental milestones

Rather than 'targets' to be measured, it's more helpful to view milestones as signals that some premature babies might need extra help. Throughout your child's early life, the healthcare team will observe their development and measure their progress against milestones.

These are usually carefully worked out targets based on the average age at which children tend to develop certain skills. For example, 8-18 months is the average age when a child will start trying to walk on their own. The milestones have been designed to help professionals spot problems early. Remember that term babies may not meet development milestones either.

Early babies are given time to catch up

If your baby is born prematurely, their milestones will be assessed from the time of their due date, not from when they were actually born. By the age of two, their development will often even out with their peers, and you can use their actual birth date instead. In very premature babies, sometimes this is extended to three years of age.

Making progress, step by step

Going back to our example of the walking milestone, if your child doesn't start walking at 10-18 months, this does not necessarily indicate a problem, and your child may well catch up later on. The healthcare team will flag it up anyway, and may refer you to a specialist, as in some cases it could be a sign that they could need some treatment or therapy to support their development.

Using milestones to your advantage

You can use milestones to your advantage in three ways:

  • To encourage your baby's development. For example, if you know that babies can start to roll over from about two months of age, you might notice them trying to flip themselves over and you can give them a helping hand
  • To keep your baby safe. You will be less likely to leave your baby lying on a sofa if you know there is a chance they could roll and fall off
  • To spot whether your little one could be falling behind. If there may be a problem in a particular area, you can seek advice more quickly.

Try to avoid comparing your child to others

It's easy to become very focused on comparing your child with other children. Some parents find themselves thinking of milestones as 'targets' that indicate the success or failure of their child. Instead, try to see them as signals that can open doors for you if help is needed. Missing a milestone doesn't necessarily mean that there's any kind of problem.

The following organisations can give you more information about the topics covered in this section.


  1. BMJ Best Practice (accessed Sept 2016) Premature newborn care, follow up, recommendations,
  2. DH (accessed Sept 2016) National Service Framework for Children, Young People and Maternity Services: Standard 8, 4,
  3. Jane E Norman, Ian A Greer (2005) Preterm labour: managing risk in clinical practice, Cambridge University Press, p126
  4. NHS Choices (accessed Sept 2016, Next review due: 09/02/2017) Health A-Z, Birth to five, Health and development, Height and weight,
  5. Rennie JA (2005) Roberton’s Textbook of Neonatology (4th edition), London, Churchill Livingstone
  6. UK/WHO (2009) Plotting preterm infants, Growth Charts - Fact Sheet 5, Royal College of Paediatrics and Child Health
  7. Vaivre-Douret L, et al (2004) Effect of positioning on the incidence of abnormalities of muscle tone in low-risk, preterm infants, 'European Journal of Paediatric Neurology' Vol 8, No 1, p21-34
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    Health problems and disability

    Premature babies are more susceptible to certain health problems than term babies, so your healthcare team will take special care when assessing your child's development.

    Last reviewed on October 3rd, 2017. Next review date October 3rd, 2020.

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Midwife @Tommys on 9 Nov 2016 - 10:02

      You should discuss this with your Health Visitor as your baby is now over 6 weeks old . It may be that you should try a different milk and see if that helps but you will need to discuss this with your Health Visitor. Try not to be too concerned

    • By Anonymous (not verified) on 8 Nov 2016 - 16:50

      our baby boy was born on week 31st. his weight on birth was 2.35 kg, now he is five Kg at age of 2.5months. however recently when we increased his milk intake from to 4oz, he is vomiting once a day and also has decreased the intake. is it a worrying sign? we went to doctor and he said thats fine and vomiting is normal but watever he takes in one diet, he vomits.

    • By Hina (not verified) on 16 Oct 2016 - 14:38

      My son head os 45 cm on his 1st birthday and that is on 15 percentile i m so worry

    • By Midwife @Tommys on 17 Oct 2016 - 09:19

      I would suggest that you ask your health visitor or Gp about your son's growth and go from there. Try not to worry at this stage.
      Take care

    • By Anonymous (not verified) on 5 Oct 2016 - 12:28

      My premmie was born at 33weeks n 5 days. She is 6months old now,very active,healthy with no complaints. She has not started sitting up but she can sit with support. When can she start sitting up

    • By Midwife @Tommys on 5 Oct 2016 - 16:02

      Hi, it is great news to hear that your daughter is doing so well. In regards to her development I think it would be good to make an appointment to discuss her developmental milestones with your Health Visitor who will look at this in context with her premature arrival too.

    • By Zain (not verified) on 9 Oct 2016 - 23:32

      My baby who was born at 35 weeks started to sit at 10 months and started to walk at 18 months my doctor said it is normal for premature babies to catch up late

    • By Midwife @Tommys on 17 Oct 2016 - 09:20

      Speak to your health visitor, he or she will be able to discuss your daughters progress and development in more detail with you, knowing your child's history.

    • By Jay Goo (not verified) on 7 Nov 2016 - 15:52

      Hi, it was same with my lo. She started sitting by herself at 8 month and made her first steps at 13 months

    • By Anonymous (not verified) on 30 Sep 2016 - 09:50

      Want to get news or advice for baby's development.

    • By Midwife @Tommys on 30 Sep 2016 - 09:56

      Hello, for further information about the early days of development for a premature baby you can download our app or you can speak to us on the pregnancy line 0800 0147 800. However if your baby is older than about 6 weeks then you should have a health visitor who you can speak to for advice about your baby's development.

    • By Princess (not verified) on 17 Apr 2020 - 09:07

      Hello my name is Princess . And I have a 8 year old who was born a premature. I have some few questions.

    • By Anonymous (not verified) on 22 Jun 2016 - 02:33

      Hi pleas some one help me my baby 9 months she has problem on her neck ( torticolis) . But some time she is good but some time is nt and the side is change time to time.

    • By Midwife @Tommys on 23 Jun 2017 - 15:48

      Hi, if your baby has been diagnosed with torticollis then they can be referred to a physio for support and exercises you can do with her which will hopefully improve this, most babies will improve with support. You can also speak with your health visitor for advice and support too.

    • By Anonymous (not verified) on 12 May 2016 - 16:34


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