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What do my baby's growth percentiles mean?
Growth charts show the pattern most healthy children follow, and small changes are normal.
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What it is
Your child’s growth is recorded on centile charts, also called growth charts [1]. In the UK these are kept in the personal child health record, known as the red book [1]. The charts show the pattern of growth that healthy children usually follow, whether they are breastfed, formula fed, or having a mixture of both [1]. Boys and girls have different charts, because boys tend to be a little heavier and taller and their growth pattern is slightly different [1].
The curved lines on the charts are called centile lines [2]. They show the average weight and height gain for babies of different ages [2]. Your baby’s weight and height may not follow a centile line exactly [2]. Measurements may go up or down by 1 centile line, but it is less common for them to cross 2 centile lines [2]. It is normal for your baby to be on different centiles for weight and length, but the two are usually fairly similar [2]. All babies are different, and your baby’s chart will not look exactly the same as another baby’s, even their own brother or sister [2].
The World Health Organization (WHO) growth standards describe normal growth from birth to 5 years under good conditions, including WHO recommendations on breastfeeding [10]. They can be applied to all children everywhere, whatever their ethnicity, socioeconomic status or type of feeding [10].
What you can do at home
- Expect rapid weight gain in the first 6 months; growth gradually slows down as your child becomes a toddler and is more active [4].
- Know that if your baby or toddler is ill, weight gain may slow down for a while, and usually returns to normal within 2 to 3 weeks [4].
- Remember that steady weight gain is one of the signs your baby is healthy and feeding well [6].
- Know that it is normal for babies to lose some weight in the first few days after birth, and most babies are at or above their birthweight by 3 weeks [6].
- Follow the weighing schedule: after the first 2 weeks, no more than once a month up to 6 months, no more than once every 2 months from 6 to 12 months, and no more than once every 3 months over the age of 1 [5]. Babies are usually weighed more often only if you ask, or if there are concerns about their health or growth [5].
- Ask your health visitor or doctor if you have questions about your child’s weight or height [3].
When to see a doctor or go to the emergency department
Talk to your health visitor or doctor if:
- your baby’s measurements cross 2 centile lines [2]
- your baby loses a large amount of weight or does not regain their birthweight by 3 weeks [6]
- your child is overweight or underweight, so you can get advice about diet and physical activity [3]
A midwife or health visitor will support you if your baby loses a large amount of weight or does not regain their birthweight by 3 weeks [6]. They will talk to you about how feeding is going, may ask to observe a feed if you are breastfeeding, and will look at your baby’s health in general [6].
Common questions
Will my baby follow one centile line exactly? No. Measurements may go up or down by 1 centile line [2]. Crossing 2 centile lines is less common, and if it happens you should talk to a health visitor [2].
My baby is on a different centile for weight and for length. Is that normal? Yes, it is normal, but the two are usually fairly similar [2].
Does my child’s height at age 2 tell me how tall they will be? Height after the age of 2 gives some indication of adult height [3]. You can use the adult height predictor in the red book if you like [3].
What happens at age 2? A health visitor may use your child’s weight and height to calculate their body mass index (BMI) and plot it on a centile chart, to check whether their weight is in the healthy range [3]. You can also use a BMI calculator if your child is 2 years old or over [3].
How often should my baby be weighed? After the first 2 weeks: no more than once a month up to 6 months, no more than once every 2 months from 6 to 12 months, and no more than once every 3 months over the age of 1 [5].
Sources
[1] NHS — “Your baby’s weight and height” (2023), section “Understanding your baby’s weight chart”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [2] NHS — “Your baby’s weight and height” (2023), section “What the centile lines mean”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [3] NHS — “Your baby’s weight and height” (2023), section “Your toddler’s weight and height”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [4] NHS — “Your baby’s weight and height” (2023), section “Your baby’s weight gain”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [5] NHS — “Your baby’s weight and height” (2023), section “How often should my baby be weighed?”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [6] NHS — “Your baby’s weight and height” (2023), section “Your baby’s weight and height”, p. 1 — https://www.nhs.uk/baby/babys-development/height-weight-and-reviews/baby-height-and-weight/ [10] WHO — “Child growth standards”, section “Child growth standards”, p. 1 — https://www.who.int/news-room/questions-and-answers/item/child-growth-standards
This guide summarises published paediatric guidelines. It is not medical advice and does not replace your paediatrician. In an emergency, call your local emergency number.
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