Babies are weighed at birth and then fairly frequently in their first weeks to make sure that they are receiving adequate nutrition and are putting on weight
Your community midwife will probably come and weigh your baby every day for their first few days. If they are gaining optimal weight, you and your baby will be discharged by the community midwife and in future be invited to bring them along to your local Well Baby Clinic, where they can be weighed and measured by your health visitor.
If you take along your baby’s Personal Child Health Record (often known as their ‘red book’), your midwife will record their weight, height and sometimes head circumference so that you have a personal record of how your baby is growing.
If your baby was born prematurely, their weight and height will be entered on the charts at the age they would be in utero. For example, if your baby is born a month early, their birth weight will be entered at 36 weeks. Your baby’s weight at the four-week mark will therefore be entered on their expected due date.
The weight charts in your baby’s red book are based on average weight gain by exclusively breastfed babies. Formula-fed babies tend to put on a little bit more weight than breastfed babies.
Baby boys tend to be a little bit bigger than baby girls and so have separate charts. If you have a baby girl, all her measurements will be added to the pink pages. If you have a baby boy, all his measurements will be added to the blue pages.
How much weight should my newborn put on?
Newborn babies tend to follow a pattern of weight change:
- Your baby will be weighed at birth
- Your baby will lose weight in the days after the birth. This is quite normal. Your baby has built up reserves in the womb to cope with the adjustment to the outside world where they must feed, breathe for themselves and begin to maintain their own body temperature
- If your baby loses more than 10% of their body weight after birth, your midwife or health visitor may look into various factors, e.g. checking they are feeding well, swallowing during feeds and producing lots of dirty and wet nappies
- Your baby’s weight loss might be more extreme depending on your birth If you had a drip during labour, your baby may have ‘retained’ some of the fluid too. They may have looked chubby or swollen after the birth and then lost a lot of this through weeing, which may contribute to weight loss. Discuss this with your midwife.
- After around the fifth day after the birth, you would not want or expect to see further weight loss or any new period of weight loss
- After about 14 days, 90% of babies return to their birth weight but it might take another week for some babies
- If you look in your baby’s red book you will see that this initial postnatal period is not mapped onto the growth charts
- Then babies gain around 112-200g each week (that is between 4 to 7 ounces) until they are around four months old.
- Weight gain after this period slows down
- If your newborn baby is premature or has been ill around the birth, discuss his expected weight gain with your baby’s paediatrician and breastfeeding specialist in NICU or SCUBU
- On average a breastfed baby will double their birth weight by the time they are six months old. At 12 months, a breastfed baby will weigh about 2.5 times their birth weight
- Exclusively breastfed babies tend to double their birth weight by five months. Breastfed babies tend to be a little leaner than formula-fed babies. This is what you would expect and is nothing to worry about – it is the optimal growth pattern, especially for their future health.
How will my baby’s height increase in the first year?
Until your baby is walking, your health visitor will describe your baby’s height as ‘length’ because they are usually lying down!
Each month, your baby will grow around 2.5cm (an inch) for the first six months of their life, but there is a range, with some babies growing faster than others. After the six-month mark, their growth in length will slow down. They will grow on average 1.25cm (half and inch) a month from now up to their first birthday.
Growth and centiles (or ‘percentiles’)
Parents can get very worried and even competitive about which centile their baby is on! However, it’s important to remember that babies, like all of us, come in a range of sizes, from long lean babies to short chubby ones. In general, your baby’s weight, length and head circumference will tend to track along a similar centile. Your health visitor will monitor your baby’s growth to check that they are on track. However, these are average growth rates and you might find that your baby moves above and below their centile, especially around growth spurts and periods of illness.
What do the height and weight centiles mean?
A baby of average weight for height will be on the 50th centile. If your baby is on the 50th centile for height and weight, this means there are 50 baby boys or girls (babies are only ever compared with babies of the same gender) of their age out of every 100 that weigh more than your baby and 49 that weigh less.
If your baby is on the 25th centile for height and weight, this means there are 75 baby boys or girls out of every 100 that weigh more and 24 that weigh less than your baby.
Failure to thrive
One of the reasons that newborn babies are weighed frequently is to make sure they are growing and developing well. Sometimes a baby’s weight gain will begin to fall off. They may even begin to lose weight, and this can be picked up at the Well Baby Clinic.
Try not to feel guilty if you are told your baby has ‘failure to thrive’ as it can be fairly common in the early days and is often easy to address.
Failure to thrive can be due to lots of different factors. Common causes are illnesses (because babies often stop feeding when they are ill), problems with poor attachment when breastfeeding, reflux and vomiting and anatomical problems such as a cleft palate that can make feeding more difficult for a baby.
The good news is that when many of these problems are picked up and, for example, the baby’s latch is corrected when breastfeeding, the baby will begin to grow and ‘thrive’ as expected.