Pregnancy information

Your baby's weight and height

Steady weight gain is one of the signs that your baby is healthy and feeding well.

It's normal for babies to lose some weight in the first few days after birth.

Your baby will be weighed during their first 2 weeks to make sure they're regaining their birthweight. Most babies are at, or above, their birth weight by 2 weeks.

A midwife or health visitor will support if your baby loses a large amount of weight or doesn't regain their birthweight by 2 weeks.

They'll talk to you about how feeding is going, possibly ask to observe a feed if you're breastfeeding, and look at your baby's health in general.

How often should my baby be weighed?

After the first 2 weeks, your baby should be weighed:

  • no more than once a month up to 6 months of age
  • no more than once every 2 months from 6 to 12 months of age
  • no more than once every 3 months over the age of 1

Your baby will usually only be weighed more often than this if you ask for it or if there are concerns about their health or growth.

Your baby's length may also be measured at some of their developmental reviews.

Understanding your baby's weight chart

Your child's growth will be recorded on centile charts in their personal child health record (PCHR), or red book.

These charts show the pattern of growth healthy children usually follow, whether they're breastfed or formula fed, or having a mixture of both.

Visit the Royal College of Paediatrics and Child Health website to see some examples of baby weight charts.

Boys and girls have different charts because boys tend to be a little heavier and taller, and their growth pattern is slightly different.

What the centile lines mean

The curved lines on the charts are called centile lines. These show the average weight and height gain for babies of different ages.

Your baby's weight and height may not follow a centile line exactly. Their measurements may go up or down by 1 centile line, but it's less common for them to cross 2 centile lines. If this happens, talk to a health visitor who can advise you.

It's normal for your baby to be on different centiles for weight and length, but the 2 are usually fairly similar.

All babies are different, and your baby's growth chart won't look exactly the same as another baby's, even their own brother or sister.

Your baby's weight gain

Usually your baby will gain weight most rapidly in the first 6 to 9 months. Their rate of growth will gradually slow down as they become a toddler and are more active.

If your baby or toddler is ill, their weight gain may slow down for a while. It will usually return to normal within 2 to 3 weeks.

Your toddler's weight and height

Your child's height after the age of 2 gives some indication of how tall they will be when they grow up. If you like, you can use the adult height predictor in your baby's red book to work it out.

Once your child gets to the age of 2, a health visitor may use their weight and height to calculate their body mass index (BMI) and plot it on a centile chart. This is a way of checking whether your child's weight is in the healthy range or not.

If they're overweight or underweight, a health visitor can give you advice about your child's diet and physical activity levels.

You can also use our BMI calculator to check your child's BMI (as long as they are 2 years old or over).

For more information about your baby or toddler's weight or height, talk to your health visitor or GP.

You can find more information on pregnancy in the 'Your Pregnancy and Birth book'.

Last Updated: 25/07/2023 07:31:02
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website