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      Baby weight

      Dad weighing baby

      Once your little bundle of joy has entered the world, it’s perfectly natural to be fascinated by your baby’s weight. Afterall, your baby’s weight is one of the first things people will ask you about your newborn, once you’ve told them whether you have had a boy or a girl!

      Like adults, babies come in all different shapes and sizes, but as your baby grows, their weight is an important sign they are feeding well and a positive indicator that your little one is happy and healthy. It’s important to keep an eye on your baby’s weight gain or loss, but that often means parents can find themselves fretting about whether or not their baby is too big or too small.

      This concern is totally understandable, but remember, your midwife will perform regular checkups to monitor your little one’s weight, while a health visitor will keep also measure the length and head size of your baby. They are there to support you if your baby loses a large amount of weight or doesn't regain their birth weight within two weeks, so they will want to know all about how feeding is going. They may even ask to see you breastfeeding your little one, just to ensure your baby’s feeding and growing as they should.

      How much should your baby weigh?

      How much your little one weighs is determined by your genetics and, importantly, your health and nutrition during your pregnancy. Although it’s easy to be distracted by your baby’s weight and how much your newborn weighs at birth, there are other factors that can impact a baby’s weight and growth in pregnancy. The midwife will be performing fundal height measurement (generally defined as the distance from the pubic bone to the top of the uterus

      measured in centimetres) during your pregnancy, in order to ensure that everything is consistent and as it should be. These measurements will be jotted down in your notes. If there any concerns, you may be referred for a growth scan, but it’s important to remember that it’s not just about the weight of the baby, but also tracking the consistency throughout pregnancy. Baby boys tend to be a little heavier than little girls, and their growth patterns are ever so slightly different. As a result they each have different centile charts. Visit the Royal College of Paediatrics and Child Health website to see some examples of baby weight charts.

      Newborn weight loss

      Every child follows a growth pattern from birth - and usually the first thing they do is lose weight! This is more common in breastfed babies. Babies can lose up to 10% of their birth weight in the first few days but should have gained this again by around day 10. It's normal for your baby to lose a bit of weight during their first few days after birth; this is because they are born with a little extra fluid, which they swiftly get rid of!

      Newborns also tend to lose weight because it can take your baby a little while to get used to drinking milk, and if you’re breastfeeding, your body also has to get used to producing milk, too.

      How often should you weigh your baby?

      It’s very easy to become a little obsessive about your baby’s weight, but after the first two weeks of birth, you really don’t need to weigh your baby that often. As a general guide, you should weigh your baby:

      • Once a month, up to six months of age

      • Once every two months from 6-12 months of age

      • Once every three months over the age of one

      Obviously, you can weigh your baby as often as you like, and you don’t need to wait until your next appointment. You can go to your local baby clinic or see your health visitor at any time, but your midwife will probably only weigh your baby more often if they have concerns about your little one’s development.

      Where to record your baby’s weight

      Towards the end of your pregnancy or after you’ve given birth, your doctor or midwife will give you a little red book. This is your baby’s personal child health record (PCHR). Don’t worry, it’s not as scary as it sounds!

      You should use this book to record your little one’s weight and height. Some parents like to keep a record of their baby’s vaccinations and illnesses as well, but your little red book should be kept up-to-date with your baby’s weight and height changes. It’s a good way to track your little one’s development, so make sure you take it to the baby clinic or your doctor. You’ll find it very useful - and it’s also a lovely record to look back on when your little one is all grown up. 

      Mum and baby

      Baby weight percentile

      In your little red book you will record your baby’s weight and growth on something called a centile chart. These charts show the pattern of growth of a healthy boy or girl.

      Whether your baby is big or small, they’re expected to put on weight at a steady pace, staying in the same range shown on the centile chart. However, just because your baby may be at the top or bottom end of the chart doesn’t mean they are over or underweight.

      The baby weight percentile graphs can look a little bit intimidating at first, but don’t worry, your health visitor will be able to show you how to track your little one’s development. It’s important to remember that all babies are different. Your baby's growth chart won't look exactly the same as another baby's, or even their own brother’s or sister’s.

      Be sure to attend your baby clinic regularly and take your little red book with you. Your baby’s growth and health will be carefully monitored and your health visitor can answer any questions or concerns you might have.

      How much weight should my baby gain?

      In the first few weeks, your baby will probably gain about 175g to 225g (6oz to 8oz) a week in weight. By about six months, they will probably have doubled their birth weight, and after this their weight gain will gradually slow down.

      The centile charts used to measure growth are just guidelines. So while your baby’s weight should normally stay within this range, don’t be worried if they have the occasional blip. These may be caused by growth spurts, illness, difficulty adjusting to solids or simply burning up more calories as they start to crawl. If you have any concerns about your baby’s growth, speak to your health visitor.

      Baby weight chart

      The following chart for baby boys and baby girls is taken from the World Health Organisation (WHO)1. This is just a guide, but if you’re worried about your baby’s weight, be sure to contact your midwife or doctor. Here’s a breakdown of average baby weights in the first year: 

      50th centile weight for baby boys
      50th centile weight for baby girls


      3.5 kg (7.8lbs)

      3.4 kg (7.8lbs)

      1 month

      4.4 kg (9.7lbs)

      4.2 kg (7.8lbs)

      2 months

      5.2 kg (11.5lbs)

      4.8 kg (10.5lbs)

      3 months

      6 kg (13.2lbs)

      5.4 kg (12lbs)

      4 months

      6.7 kg (14.8lbs)

      6.2 kg (13.7lbs)

      5 months

      7.4 kg (16.3lbs)

      6.7 kg (14.7lbs)

      6 months

      7.9 kg (17.4lbs)

      7.2 kg (15.8lbs)

      7 months

      8.4 kg (18.5lbs)

      7.7 kg (17lbs)

      8 months

      8.9 kg (19.6lbs)

      8.1 kg (18lbs)

      9 months

      9.3 kg (20.5lbs)

      8.5 kg (18.7lbs)

      10 months

      9.7 kg (21.4lbs)

      8.8 kg (19.4lbs)

      11 months

      10 kg (22lbs)

      9.2 kg (20.3lbs)

      12 months

      10.3 kg (22.7lbs)

      9.5 kg (21lbs)

      Premature baby weight 

      A baby is considered to be born prematurely if they arrive before 37 weeks. If your little one was born prematurely, they’ll have different nutritional needs because they grow faster than full-term babies.

      If your baby is premature, they’ll also have a slightly different baby weight chart. For more information on how to monitor and measure the weight and health of preterm babies, visit the Royal College of Paediatrics and Child Health .

      Do you have any questions about your baby’s weight?

      If you'd like to know more about your little one’s weight or have any questions about baby weight gain, why not give one of our friendly experts a call on 0800 977 8880. Or, ask us a question online, instantly, using Live Chat Monday to Friday, 8am - 8pm.


      1. The WHO Child Growth Standards, Accessed October 2018 

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