Need to talk? Call 1800 882 436.
It's a free call with a maternal child health nurse. *call charges may apply from your mobile

Is it an emergency? Dial 000
If you need urgent medical help, call triple zero immediately.

beginning of content

Failure to thrive

5-minute read

Failure to thrive (FTT), otherwise called growth faltering, slow growth or poor growth, is a condition that refers to when a baby does not gain weight and does not grow as they need to. Although every baby is unique, there are some expectations around the amount of weight they need to gain to grow normally. Development, brain growth and general health can all be affected when a baby’s weight and size do not increase over time.

What is failure to thrive?

Babies who are diagnosed as being 'failing to thrive' weigh persistently below the 3rd percentile and have crossed 2 or more percentiles over time. All babies have periods when they gain or lose weight. Most babies lose weight after they are born — on average, between 5-10% in their first week. However, the majority then regain their birth weight by 2 weeks of age.

Sometimes a baby’s weight is stable, but generally, it is unusual for babies to lose weight unless they are unwell.

When a baby is consistently losing weight and not growing at the expected rate for their age and gender, they may be diagnosed as having 'failure to thrive'.

What causes failure to thrive?

Physical or organic causes

There are a few reasons why FTT can happen. Sometimes there’s a physical or organic reason which causes the baby not to absorb or metabolise nutrients. This means they are unable to use the food (milk or solids) they’re eating to fuel their growth.

Common medical conditions causing FTT include:

Environmental causes

Environmental factors can cause FTT, most commonly because the baby isn’t being fed the right amount of food to fuel their growth.

Some common environmental causes for FTT include:

  • lack of opportunity — the baby is not offered regular, nutritious milk and/or food
  • family homelessness and/or poverty
  • parents experiencing mental health issues and an inability to provide adequate food
  • parents missing their baby’s cues for hunger

Combination of causes

Sometimes FTT is caused by a combination of medical and environmental factors. Babies can refuse to feed or become fussy feeders because of an undiagnosed and untreated medical condition. Babies can also continue to be fussy feeders after they have recovered from an illness.

Babies who were small for gestational age (SGA) or premature, can take longer to gain weight after birth and ‘catch-up’ with babies of the same age.

What if there’s no apparent cause for failure to thrive?

It’s not always clear what causes a baby to fail to thrive and sometimes no specific cause is found. This makes it difficult for parents who may feel they’re doing all they can to feed their baby regularly and support them to grow.

It’s not uncommon for parents to feel stressed and anxious about their baby’s growth, especially when their baby is diagnosed with FTT. Just as a parent’s emotional distress can contribute to FTT, parental anxiety is a common outcome when a baby does not grow as they need to.

However, some babies are smaller because of genetics. Parents who are shorter and smaller than average are more likely to have children with the same characteristics.

How do I measure my baby’s growth?

It’s relatively easy to measure how your baby is growing. Their weight, head circumference and length are all indicators of how healthy they are and how big they are getting. Growth charts are used to plot changes in a child’s measurements. Since 2013, WHO growth charts are recommended in Australia to measure children aged between birth and 2 years.

On average, most babies will:

  • double their birth weight by around 4 months of age, and triple it by 13 months
  • increase their birth length 1.5 times in the first 12 months
  • increase their birth head circumference by around 11 cm in 12 months

What happens if my baby has failure to thrive?

Your baby will need to be examined by a paediatrician. Sometimes more frequent breast or formula feeds and for babies over 6 months, increased solids, are enough to provide extra kilojoules to support increased growth. If FTT is not related to feeding or an underlying disease, medical practitioners can investigate further.

Regular weight and growth checks are important for babies who are diagnosed as having FTT. Check with your child health nurse, doctor and paediatrician to monitor your baby’s growth.

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call 7 days a week.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: June 2021


Back To Top

Need more information?

Understanding baby growth charts

Baby (or infant) growth charts indicate how your baby is growing, recording changes in your baby's length, weight and head circumference.

Read more on Pregnancy, Birth & Baby website

Growth charts for babies & children | Raising Children Network

Child growth charts give a guide to how well children are growing. Growth usually follows a typical pattern, which is influenced by genes and environment.

Read more on raisingchildren.net.au website

Your baby's growth and development - 1 month old

Your baby starts developing from the moment they are born. At 1 month, cuddling, sleeping and feeding are all that really matters to your baby.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 10 months old

A 10-month-old will be very active. As a parent, you’ll probably be chasing them around as they crawl, and be learning more about their developing personality.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 12 months old

At 12 months, your baby is now a toddler. If they haven’t already, it won’t be long now before they take their first steps, develop a sense of humour, and tell you they love you.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 5 months old

At 5 months, your baby is quickly growing and developing. They may soon be sitting up on their own, preparing for solid foods and learning new language skills.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 7 months old

Your 7-month-old baby is growing fast and may even be sitting up on their own and eating solid foods. Learn more here about how your baby is developing when they reach 7 months.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 3 months old

By 3 months, your baby will have formed a strong attachment to you. They will respond with lots of smiles, and you can really enjoy your baby as they develop.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 11 months old

At 11 months old, your baby is almost a toddler – you’ll probably be surprised at how quickly they can move around your home and how independent they are becoming.

Read more on Pregnancy, Birth & Baby website

Your baby's growth and development - 8 months old

At 8 months old, your baby will start to explore their little world. It might mean more running around for you, but it's a great time to watch them learn.

Read more on Pregnancy, Birth & Baby website

Call us and speak to a Maternal Child Health Nurse for personal advice and guidance.

Need further advice or guidance from our maternal child health nurses?

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.