My feed

How much weight should my baby gain in the first year?

Babies are born in all shapes, sizes and weights. What counts from birth onward is the rate at which they gain weight and grow. You want to be tracking the arc of the centile they were born on, shown on the weight charts in their red book. Your baby will be measured at certain ages to check that he’s putting on weight at the expected rate. If his weight gain has slowed, it could be for a number of reasons, and your midwives and health visitors will be able to help you get things back on course.

By Mumsnet HQ | Last updated Jul 13, 2021

Small baby on scales with fingers in mouth

How much should my baby weigh?

Your baby will lose some of their birth weight in their first few days but this is nothing to be concerned about. Babies are born with some extra fluid and the loss of this is entirely normal. Most babies lose 7-10% of their birth weight in the first days.

If your breastfed baby has lost more than this, your midwife or health visitor may recommend that you supplement feeding with formula. About 80% of newborns will reach their birth weight again within their first two weeks, though this may take a little longer for some.

From two weeks of age, your baby will normally gain 110-200g (four to seven ounces) per week up to four months. After this, weight gain slows down.

By six months, most babies have doubled in weight. By the time they are one, they usually weigh three times their birth weight and have added roughly 25cm to their height.

And by the time they’ve hit two, your toddler will usually be quadruple their birth weight.

How often will my baby be weighed?

Your baby’s weight, height and head circumference will be measured by your health visitor within the first two weeks to make sure that he's regaining his lost birth weight. After this you’ll need to take him to be weighed at these intervals or thereabouts:

  • once a month up to six months of age

  • once every two months from six to 12 months

  • no more than once every three months from 12 months

How is my baby’s weight measured?

It’s important to make sure that your baby is weighed in the same way every time, preferably naked, to ensure accuracy.

Close up of an NHS baby book

This information is recorded in your baby’s Personal Child Health Record (PCHR) also known as the ‘red book’ (nothing to do with This Is Your Life). You’ll receive this either before or shortly after your baby is born. It’s used to record your baby’s weight, height and measurements as well as vaccinations and developmental milestones. You should bring this with you to every GP or health visitor appointment.

Your baby’s weight is recorded on the centile charts in their red book. The curved lines you’ll see on the charts are centile lines – they’re a sort of rough guide for where your baby’s weight should be.

He will have been weighed and measured at birth and his weight recorded as a ‘centile’. He might be on the 9th centile or the 91st. Where they start isn’t important; what’s important is that weight continues more or less on that curve.

Babies' heights are also recorded in percentiles. Both measurements are recorded on separate charts in your baby’s PCHR and it is common that they will register at different centiles.

Babies don't gain weight in nice straight lines and as long as they are healthy, alert and have plenty of wet nappies then feeding is probably going well.

All babies are different so don’t expect your child’s chart to look the same as another’s. For example, boys and girls have different charts as boys tend to be heavier.

If your baby was born prematurely, his weight will be recorded differently again. For example, if they were born six weeks early, the weight recorded when they are six weeks old will be entered at his due date weight on the centile charts.

The centile charts do not record the first two weeks when your baby is regaining his birth weight.

My health visitor said my baby is ‘failing to thrive’. What does this mean?

It can be scary when you hear the words ‘failure to thrive’ but this is simply a medical term used to describe the health of an infant that is not gaining weight at the expected rate. Your health visitor or GP will usually determine if this is the case by measuring your baby’s height, weight and head circumference against a growth chart. They will then work with you to determine the underlying cause.

What should I do if my baby isn’t gaining weight?

Your baby’s rate of weight gain will usually follow a percentile line closely. It’s common for weight to cross one percentile line, however, if weight loss extends to two percentile lines, your health visitor may be concerned. They will usually want to monitor your baby over the following two weeks to see if the weight loss is temporary. This means that they will weigh your baby more frequently.

My son was born on the 75th percentile. By three months he'd dropped to the 25th percentile – not for any particular reason, he was just a slow grower. I was stressed about it but he seemed fine in every other way so I carried on exclusively breastfeeding.

Try not to worry too much. There may be a number of reasons why your baby is not gaining weight at the desired rate. You may feel under increased pressure with additional weigh-ins or health visitor appointments but remember that they are there to help you as well as your baby and often the problem is easily remedied with their support.

Is my baby getting enough to eat?

The most common reason for slow weight gain in babies is that they are not getting enough to eat. This can often be remedied by increasing the frequency with which you feed.

While it’s easier to measure how much a baby is getting when they are bottle fed, it can be difficult to know if you are breastfeeding. Once your milk comes in on about day three or four, you should start noticing six to eight wet nappies a day and at least two dirty nappies in 24 hours, which tells you your baby is getting enough milk.

If you are concerned that your baby is not getting enough milk, then it’s worth asking your health visitor to observe you feeding. It could be as simple as adjusting the position your baby feeds in, improving his latch or making sure you feed from both breasts in a single feed. Your health visitor can give you further advice on breastfeeding technique but you may also find it helps to visit your local breastfeeding support group or seek out the help of a lactation consultant.

What else could be causing my baby’s slow weight gain?

If you’re confident that your baby is getting enough to eat, it’s worth having a think about whether one of these issues could be the cause:

  • An infection. Any illness, vomiting or diarrhoea may result in some temporary weight loss. Infections in the mouth or even a urinary tract infection will also affect your baby’s ability to feed.

  • Reflux or a digestive issue. Persistent reflux may make feeding uncomfortable for your baby and reduce his desire to feed.

  • A medical condition. A condition like cleft palate or tongue tie makes it harder to suckle.

  • In later months, your baby may be having trouble weaning onto solid foods meaning he isn't getting all the calories he needs to gain weight.

  • They could simply be a slow gainer. When all other explanations have been ruled out, it could be the case that your baby is just gaining weight at a slightly slower rate than the averages being measured against.

Do breastfed babies gain more weight than formula-fed babies?

In the first two to three months, breastfed babies tend to gain weight quicker than those fed on formula alone. However, in the first couple of weeks weight gain may be slower as both you and your baby settle into a feeding routine.

Any rapid weight gain that breastfed babies experience usually tapers off by the fourth month and by the age of one, babies that have been exclusively breastfed may even weigh less than formula-fed babies.

By the age of two, things will have evened out and there should be no difference in weight gain between a baby who was exclusively breastfed and a formula-fed child.

Should I give my baby formula or solid foods to help him gain weight?

If your breastfed baby is slow to gain weight and it cannot be explained, your GP may recommend that you introduce formula. This doesn't mean you have to stop breastfeeding – the formula will just be used as a ‘top-up’ to supplement your breastmilk.

If your baby is bottle fed and not gaining weight you might be considering introducing solid foods to boost his calorie intake. Babies under six months tend to get all the nutrition they need from breastmilk or formula. It is recommended that you wait until your baby is at least six months before weaning onto solids. Introducing solid foods too early can reduce your baby’s desire for milk, which is a much better source of nutrition and calories at this age.

If you do think solid foods will help your baby gain weight, discuss it with your health visitor before ploughing ahead.

How can I increase my milk supply?

If your baby’s slow weight gain is because he is not getting enough milk, you may need to increase the frequency with which you feed.

If you bottle feed your baby, this is more easily done. When you are breastfeeding, you might be concerned about whether you can produce enough milk. If you need to boost your milk supply, you can try the following tricks:

  • Skin-to-skin contact will encourage your body to produce milk. Never will you have a better excuse to lie on the sofa for hours at a time with your top off, your baby on your chest and a box set on – so make the most of it. Putting your baby to your breast every two to three hours or bottle feeding near the breast will both provide opportunities for skin-to-skin time. Another good opportunity for skin-to-skin cuddles will be when your baby is full and ready to sleep.

  • Nothing helps to produce milk better than frequent feeding. The more your baby feeds, the more milk you will produce. Even after your baby has finished feeding, holding him to your breast and allowing him to suckle will also help with milk stimulation.

  • Don’t wait until your baby is hungry to feed. Instead, choose a time of day when he is happy and comfortable. Learn to read early feeding cues such as your baby putting his fist in his mouth or opening his mouth while moving his head from side to side. It's easier to feed a happy baby than one that is upset.

  • Let your baby feed on demand and for as long as he wants. It takes time and patience but just clear your diary for a few days and make the most of the time relaxing at home.

  • Make sure to feed from both breasts in a single sitting.

  • You could use a lactation aid which will allow your baby to get milk from a small tube attached to your breast. Talk to your health visitor about whether this might help.

  • Use breast compression when you are feeding as you would if you were expressing by hand, by pressing your thumb and forefinger on the areola gently while feeding.

  • Expressing milk in between feeds can stimulate your breasts to produce more milk, too. You can freeze this milk for your baby to have at another time.

  • If your baby gets sleepy during a feed, try tickling his feet to keep him awake and actively feeding.

My first daughter lost weight and hardly gained any in the first few weeks so I had to mix feed. My second daughter was slow to gain weight but she did eventually and that is the important thing.

Some women also find that herbal remedies and certain foods help their milk supply:

  • Oats. If you don’t like porridge, then flapjacks are another good alternative.

  • Fenugreek. This can be eaten in either seed or tablet form and is found at most health-food shops.

  • Brewer’s Yeast. This is also available in tablet form.

  • Non-alcoholic beer has the same properties.

  • Fennel. If you don’t like the strong taste of the vegetable, try drinking it as a tea.

Celebrating a new arrival? Create your very own Amazon baby wishlist and get 15% off baby items when you spend £200 or more.