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Every baby is unique and each child's weight and length will differ, but there are some factors that can contribute to how much your baby weighs, such as genetics and the substance of their food which can depend on the mother's diet.
If you yourself were a bigger baby, there’s a chance your little one is more likely to be bigger too. And if you ensure you’re eating plenty of nutrients, your breast milk will be have all the ingredients to help your baby grow as big and strong as possible.
In a recent study in the Journal of Epidemiology, researchers from the University of Bristol concluded that avoiding alcohol completely throughout pregnancy will also help babies to reach a healthy birthweight even before they are born.
The first thing babies do on their pattern of growth after birth is shrink. It takes a while for your newborn to get used to drinking milk rather than getting food through the placenta (and if you’re breastfeeding, for you to start making it), which means they can lose up to 10% of their weight in the days following birth.
But by about 10 days old, your baby should start to put it on again.
What is a centile chart?
Your health visitor will plot your baby’s weight gain for the first few weeks (then less regularly as they grows up) in their health record on a baby weight chart, also known as a centile chart.
Your centile chart shows lines that represent a zone within which your baby is expected to grow normally. If they’re on the top line, or centile, it doesn’t mean they’re overweight. Equally, your little one isn’t necessarily underweight if they’re on the lower line. Either way, your baby is still within what’s considered the normal range.
If your baby jumps up or down to the next centile, or begins to go beyond the zone altogether, speak to your health visitor. But it’s not usually anything to be concerned about. Babies will often go through growth spurts, gaining nothing for a couple of weeks, then catching up in one go.
Some little ones may not follow the baby weight chart very well but this doesn’t mean they’re ill. Exclusively breastfed babies, premature babies or twins all show slightly different weight gain progress. In this case, your health visitor will use different, specialised charts to check your child is gaining weight properly.
We’ve worked out an outline of what your baby should be weighing with a month by month guide, but for a more detailed overview you can take a look at a centile chart which shows week by week measurements.
Baby girl growth chart
Birth: 5.5lbs to 10lbs
1 month: 6.6 to 14
3 months: 7.7 to 15
6 months: 11.6 to 22
9 months: 13 to 25
12 months: 14.3 to 27
Baby boy growth chart
Birth: 5.6 to 11.2
1 month: 6.6 to 13.2
3 months: 9.9 to 18.7
6 months: 11.9 to 23
9 months: 14.3 to 26.2
12 months: 15.6 to 28.4
How often should my baby be weighed?
Your baby’s weight will fluctuate the most in the first few weeks so it’s normal to have them weighed after the first fortnight to check their weight is steadily increasing after taking an initial dip.
Your baby should then be weighed once a month for their first six months, there’s no need to weigh them more than that.
From being six to 12 months old your baby should be weighed no more than every other month.
Once your little one has passed their first birthday they shouldn’t need weighing more than once every three months.
Usually your baby will gain weight most rapidly in the first six to nine 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 two to three weeks.
If you have any concerns that your baby is underweight or overweight your health visitor can look into this with you.
Is my baby putting on weight properly?
Your baby will rely on either breast or bottle to give them the nutrients that they need to keep them growing at the right pace.
You can check if your baby is taking in all those nutrients properly by looking out for some of these signs. Here’s a rough checklist that should show if they’re getting enough nutrition in their milk:
- They have yellowy, seedy poo five times a day to begin with, slowing to an average of one a day from threee months onwards
- Their nappy is wet and/or heavy. Hold a fresh one in the other hand and compare the weight of the two if you’re unsure
- Their wee is clear. If it’s yellow your baby could be dehydrated and not getting enough to drink
- A bottle has the advantage of giving an accurate measure of how much they’ve taken
- At the breast your baby should be making gulping and swallowing noises
- They’re happy after a feed and don’t cry for more
- They’re following the height and weight chart to the satisfaction of your doctor or health visitor
Remember, it’s normal to go a few weeks where there’s no gain, sometimes even a small weight loss, usually followed by a growth spurt.