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Baby weight gain concerns: here we look at what to do if you’re breastfeeding and your baby is not gaining weight or is only gaining weight slowly.

Babies are weighed at birth and at intervals afterwards, as weight gain can be an important indicator of health and well-being.  Weight is usually tracked for the first weeks and months.

Talk to your midwife or health visitor about how often your baby needs to be weighed. 

What to expect

After birth, babies almost always lose a little weight (because of urine and meconium loss) in the first few days. This is usually no more than 10% (so a baby weighing 3.5kg at birth might lose 350g in the first four days). By day 4-5, most babies will have stopped losing weight.

"By two weeks old, weight loss is usually regained, and babies who are feeding well and effectively are back up to birth weight within 10-14 days."

What can you do if your baby is not gaining weight?

If your baby hasn't re-gained their birth weight, if you're breastfeeding, you may need to offer them more breastfeeds.

Ask your midwife to observe you feeding, to check your baby is taking in milk, too.

Sometimes, a change in the way your baby is positioned at your breast can help make feeds more effective.

Keep your baby skin to skin with you, which will probably increase the times you feed. It also helps to offer both breasts.

How your baby's weight is recorded

After the first two weeks your baby’s weight will be recorded on a centile chart. Most babies track more or less the same line on the chart as they get older, but it can be quite normal to veer away from the line, and also to find a ‘new line’ to track.  Weight is only one aspect of your baby’s health and development.

Centile charts are used to track a baby’s weight.  In the UK, the data they are based on comes from an international survey, which recorded the growth of healthy babies who were exclusively or predominantly breastfed for four to six months. A baby on the 25th centile is heavier than 24% of babies the same age, and lighter than 74% of babies the same age. 

"Whenever your baby is weighed, make sure it is done accurately. Your baby should be naked each time."

Check the reading yourself, and the way it is written in your records (mistakes sometimes happen!). Sometimes, the translation from metric to imperial is incorrect, for example.

What if my baby’s weight gain is slower than expected?

Most babies like this are basically healthy with no underlying illness or difficulty. They may be naturally slow gainers – that’s just the way they are. 

However, you and your health visitor can discuss this, and if there is concern, and no actual urgency, the first step to address the issue is normally is to try to increase your baby’s intake of milk. 

You can:

  • try breastfeeding more often, day and night,
  • offer at least both breasts at each feed,
  • try ‘switch nursing’ when you aim to use each breast several times at each feed or
  • try breast compression.

Keeping your baby close to you, skin to skin when possible, almost always results in your baby feeding more often. This might be something you can try intensively, over a period of a few days (sometimes called a ‘babymoon’).

Ask a midwife, health visitor or breastfeeding counsellor to observe a feed, and to help you see if your baby is taking in milk effectively, and isn’t hampered by a tongue tie, or by not having a good mouthful of breast to enable plenty of milk. 

You can speak to a breastfeeding counsellor about all of these and other ways to increase your baby’s intake. 

What about giving my baby expressed breastmilk?

Expressing and offering expressed breastmilk in addition to direct breastfeeds is another possibility, but if your baby is feeding well from the breast, then the extra direct breastfeeds suggested above are an easier option. 

What about donor milk?

Donor milk – breastmilk from other mothers – may be available from a hospital based milk bank. Mostly, milk banks make milk available to vulnerable, pre-term or sick babies still under hospital care. 

Donor milk is also available via private milk donation schemes.  

Does my baby need formula? 

If the extra breastfeeding/breastmilk doesn’t make sufficient difference, if donor milk is not an option, and there is still concern about your baby’s weight, then using formula may be medically necessary to help your baby grow. This does not have to mean you stop breastfeeding if you don’t want to, and it does not mean the positive health impact of breastfeeding is wiped out.  

If you are keen to maintain your breastfeeding, then formula can be given as well as continuing to breastfeed. The amount of formula can be limited, and you may be able to drop it once your baby’s weight is ok, if that’s what you prefer. Talk about this with a breastfeeding counsellor or a healthcare professional. 

Should my baby have solid food?

Generally speaking, babies under six months don’t benefit from food other than milk (formula or breast). Solids may not actually increase a baby’s calorie intake, and may even mean a baby takes less milk than before so it may be an ineffective way to address low weight.

However, a few individual babies who are having problems staying well-nourished on milk alone may be better off with additional solid food, so this would be something to discuss with your health visitor or doctor.

This page was last reviewed in January 2018.

Further information

NCT supports all parents, however they feed their baby. If you have questions, concerns or need support, you can speak to a breastfeeding counsellor by calling our helpline on 0300 330 0700, whether you are exclusively breastfeeding or using formula milk. Breastfeeding counsellors have had extensive training, will listen without judging or criticising and will offer relevant information and suggestions. You can also find more useful articles here.

National Breastfeeding Line (government funded): 0300 100 021.

NHS information on mastitis.

Best Beginnings - Bump to Breastfeeding DVD Chapter 7 'Overcoming Challenges'. Managing Breastfeeding – dealing with difficult times.

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