If you've ever taken your child to a maternal, child and family health nurse for a growth check, you might have felt a mix of curiosity and anxiety.
As health professionals, we're often asked: is my baby gaining enough weight? Am I feeding enough? Why did they drop a percentile? Why is my friend's baby bigger than mine? Am I doing something wrong?
In most cases, the answer is that there is nothing wrong at all. Let's look at what the measurements actually mean and we'll answer some questions that commonly arise during these appointments.
What actually happens at a growth check?
Growth checks are usually done by a maternal, child and family health nurse at a community health centre, or by your family GP.
Each state and territory, as well as New Zealand , has its own schedule of recommended growth and development checks. In Victoria , for example, appointments are booked when your baby is aged two weeks, four weeks, eight weeks, four months, eight months, 12 months, 18 months, two years, and three and a half years.
In the early weeks, when feeding is still being established and child growth is rapid, these appointment can help identify feeding difficulties.
First, the nurse will observe your baby or child, then they will weigh them, measure their length (if they're babies) or height, and measure their head circumference. They plot these numbers on a growth chart in your child's health record or the Well Child Tamariki Ora book in New Zealand.
The nurse will check your child's alertness, appearance and muscle tone. They will also ask questions about feeding, sleep, wet/dirty nappies and any recent changes.
Nurses are there to support you as a new parent. They provide reassurance and a chance to ask questions to help build confidence during a period that can feel uncertain.
Over time, growth checks allow nurses to see if your child is growing and developing at an expected rate.
For toddlers and preschoolers, the nurse will check for typical development in behaviour, language and play . If required, they will provide support or referrals to a GP who may then refer to a paediatrician, speech pathologist, occupational therapist, or psychologist, depending on the child's needs.
What do the dots on a growth chart really mean?
Growth charts in Australia and New Zealand are based on the World Health Organization's Child Growth Standards, which reflect optimal growth for healthy, breastfed children.
They provide context for your child's growth through a reference population of children of the same age and sex. The curved lines are called percentiles.
- a child on the 50th percentile is right in the middle
- a child on the 25th percentile is smaller than average
- a child on the 85th percentile is larger than average.
If your child is on the 25th percentile for weight, it means that if 100 children of the same age and sex were lined up in increasing order of weight, your child would be number 25. So 75 children would weigh more and 24 would weigh less.
A single measurement tells very little. The pattern of the weight over time is even more important.
But there is no "ideal" percentile. Every child grows at their own pace and this can be influenced by their genetics , ethnicity , birthweight and gestation . Even siblings or twins may follow different patterns.
When should parents be concerned?
Small fluctuations on the chart are common, as babies grow in spurts. But nurses may look more closely if a child:
- crosses several percentile lines over time - either in an upward or downward trend
- is showing signs of feeding difficulties or dehydration
- appears unwell.
Even in these cases, the approach is careful assessment, not alarm, and your nurse might suggest additional checks. This helps see whether a feeding adjustment is working, or whether something else might need attention.
In most cases, extra visits end with reassurance. When there is a concern, extra visits allow things to be identified and addressed early.
3 common questions answered
1. When should I consider supplementing with formula?
Breastfeeding is recommended where possible. But there are situations where supplementing with formula might be recommended - for example, when there are concerns about weight gain. In these cases, we always recommend to discuss supplementing with your trusted health care provider.
Your nurse is there to support your child and reassure you - not to judge how you feed them.
2. Should I start solids early if my baby is 'big'?
In short, no. The guidelines recommend introducing solids at around six months . This should be done when babies show developmental readiness, not because of their size or percentile.
Breastmilk or formula still meets all nutritional needs until around six months.
Starting solids early may increase risks of choking, tummy upset and a greater chance of being overweight later in life .
3. Why doesn't growth happen steadily week to week?
Babies grow in spurts, not in smooth lines and weight can vary with feeding, sleep and any recent illness.
Periods of rapid growth often occur in the early weeks, around six to eight weeks, three to four months, and around six months with babies growing rapidly throughout the first year of life . During these times, babies may feed more or seem unsettled.
Where to find more support
For more support, contact your local GP and consider asking for a referral to a lactation consultant, paediatrician or dietitian.
As part of the Australian government's Pregnancy, Birth and Baby program, you can phone (1800 882 436) or video call a maternal and child health nurses for free, seven days a week from 7am to midnight. Or for breastfeeding issues, call the Breastfeeding Helpline on 1800 mum 2 mum (1800 686 268).
For parents in New Zealand, the government's Plunketline (0800 933 922) is available 24-7 for advice about child health and parenting.
Amit Arora receives funding from the Australlian National Health and Medical Research Council and NSW Ministry of Health.
Hannah Dahlen receives funding from Australian Research Council, the National Health and Medical Research Council and Medical Research Future Fund.
Jessica Appleton is a board member with Australian College of Children and Young People's Nurses.
Lynn Kemp receives funding from Australian Research Council, National Health and Medical Research Council and the Medical Research Future Fund.
