How to interpret growth charts for babies and toddlers?

by | Mar 3, 2020 | 6-12 months, Birth to 6 months, Medical Conditions, Toddler Nutrition

Growth charts are often seen as growth lines that are only used by healthcare professionals. For me as a dietitian, growth charts are one of the best ways for inter-professional communications about the general health of a child. That is why it is so important for us as to document growth and ideally to do that using the same growth charts used by all healthcare professionals involved in a child’s care. If you are in the UK, you will have a “red book” which you as parents own and need to take to consultations with any healthcare professional, where a measurement may be taken. Although, every healthcare professional should document a measurement in your growth chart, this is often forgotten, so the first message of this blog is to remind the person taking the weight/length to document  this on your child’s growth chart.

Everybody is supposed to use the WHO growth charts. These are growth reference charts of babies/children that have been breasted exclusively until 6 months and include children from range of cultural and social background all across the world. So it does not matter if you are from European, Asian or African descent and what the socio-economic status is, these are the correct growth charts. Growth charts can be downloaded from the WHO chart and you can even get their software for free.

All babies and toddlers should have their weight done regularly.  When they are young, this usually occurs every 2nd week  to 1 x per month, but less frequently when older. The frequency may also depend on whether there are any concerns about growth. Stature should also be measured, which is in the form of length until 2 years (this is lying down) and height (standing up) after 2 years. Head circumference should be measured until 2 years of age.  Although it seems easy to perform measurements, it is in fact not that simple and the procedure of the WHO should be used to measure (you can find this online). In addition, the scales should be electronic and regularly calibrated and the right length device used.

Weight is an indication of short-term nutrition, meaning it drops and or goes up rapidly. So it’s a good marker to indicate how your baby is doing now and can capture weight loss because of illness quickly or rapid weight gain due to over-feeding. Length (or height) and head circumference on the other hand is a more long-term indicator of growth, so takes a longer time to drop if unwell and also takes a longer time to catch up once it has dropped. A drop in length/head circumference over time is therefore much more worrying as indicates that growth has not been optimal for some time.

It is crucial that all measurements are performed to assess growth (meaning weight, length and head circumference where appropriate), because your baby may be small, but perfectly in proportion with the length and has always grown along the lower centile. Conversely your baby may be quite robust, but has dropped in centiles well below where the length is tracking.

I am sure you have all heard of faltering growth, which is the term replacing the old failure to thrive, the latter having a negative connotation as being seen as a “failure”, which of course is not true. Faltering growth indicates a downward trend (usually defined as 2 centile lines in the UK or 1 z-score outside of the UK) over time in weight and should be investigated if this is identified. If your child has dropped 2 centiles, its firstly important to measure length and head circumference to see whether this is acute or has affected these long-term markers. Any growth faltering should be investigated as there can be medical reasons for having poor growth. Ideally  baby or toddler with growth faltering should be seen by a paediatric dietitian.


Of course, growth monitoring is also crucial for establishing if your baby is putting on weight too fast. Again, its absolutely crucial that this is interpreted together with the length. If a baby is tall and the weight moving towards the same centile as the length, then of course there is no concern, but if a baby’s weight is going up beyond where the length is, then it is worth discussing this with your healthcare professional. In babies and toddlers BMI is usually used as marker of overweight and obesity.  Guidance from the WHO indicates that babies and toddlers with a BMI > 2 z-scores or in the UK > 91st centile – 98th centile may be overweight and > 98th centile may be obese. If this is the case, a discussion with your healthcare professional also is advised.


So, what is my final message. Aim to get growth measurements done regularly (in particular when your baby is small), take your growth chart and remind healthcare professionals to complete this and finally and most importantly, growth can only be interpreted if you have both weight and length/height and where appropriate head circumference.