Failure to Thrive Or Failure to gain weight

Understanding failure to thrive or gain weight

The term failure to thrive or gain weight is used to describe a child who is undernourished, but it is not a disease or disorder in and of itself. Kids who fail to thrive are unable to take in, keep, or use the calories they need to help them grow and gain enough weight, and the reasons for this vary

The condition is usually diagnosed in toddlerhood and infancy, which is an important time in physical and mental development. A child’s brain develops as much in their first year after birth as it does during the rest of the child’s life, and poor nutrition during this time can have a harmful lasting effect on the brain’s development.

Most babies double their birth weight within the first four months and triple it by age one. Children who fail to thrive don’t meet these milestones. Occasionally, children who seem to be growing well may gain less weight later on and height growth may be affected.

If the condition continues, children may begin to:

  • Avoid eye contact
  • Lose interest in their surroundings
  • Become fussy
  • Not reach important milestones such as sitting up, walking and talking at the normal age

What causes slow growth in babies?

Some things that can cause slow growth in babies include:

  • Not enough food offered
  • The child eats too little
  • Health problems with the digestive system
  • Food intolerance
  • An ongoing illness or disorder
  • Infections
  • Metabolic disorders

Not enough food offered

If a parent or child has problems breastfeeding, it may cause a lack in calorie intake. When transitioning from breastfeeding to solid foods it may be difficult to accurately gauge how much solid food is necessary.

Child eats too little

If a child is born prematurely, has developmental delays or conditions such as autism they may have trouble eating enough food. Children with autism can have an aversion to food with certain textures or tastes.

Digestive health problems

Health conditions such as gastroesophageal reflux (GORD), chronic diarrhoea, chronic liver disease, celiac disease, and cystic fibrosis can prevent a child from gaining weight.

Gastroesophageal reflux can cause the oesophagus to become irritated, which can make eating an uncomfortable or even painful experience. Persistent diarrhoea can make it difficult for the body to retain the nutrients and calories from food, since transit time of the food (mouth to anus) is reduced significantly. Cystic fibrosis, celiac disease and chronic liver disease can cause problems with the body’s ability to retain and absorb nutrients. While a child may eat a lot, their body may not absorb or retain enough of the food and nutrients. Children with celiac disease are allergic to gluten, which is a protein found in wheat and other grains. The immune system has an abnormal response to the protein, which damages the lining of the intestines so it is unable to absorb nutrients properly.

Food intolerance

A food intolerance is different from a food allergy. An intolerance means the body is sensitive to certain foods. For example, an intolerance to the A1 milk protein means the body can’t absorb food containing this protein, which can lead to a failure to thrive. Some kids do better on A2 milk, widely available across many parts of Australia, being the milk produced by a certain type of cow.

Ongoing illness or disease

A child who was born prematurely or has a cleft lip or palate may have trouble eating and not take in enough calories to support normal growth. Conditions that involve the lungs, heart or endocrine system can increase the calorie intake needs of a child, and make it hard for them to eat enough to keep up.


Urinary tract infections, tuberculosis, parasites and other infections can cause the body to use nutrients rapidly and decrease a child’s appetite. This can cause a long- or short-term failure to thrive.

Metabolic disorders

Metabolic disorders make it hard for the body to break down, process or take energy from food. This can also cause a child to have trouble eating or keeping food down.

Sometimes a mix of environmental factors and medical problems can lead to a failure to thrive. If a baby has severe gastroesophageal reflux and is reluctant to eat, the baby may become upset and frustrated, which means the child may not be able to get enough food.

Diagnosing failure to thrive

Most babies go through periods when their weight gain levels out or they lose weight. This is not unusual, however if this occurs for three months in a row during the first year after birth, doctors may become concerned.

There is a standard growth chart that doctors use to plot length, weight and head circumference, which is measured at each check-up. Children may have failure to thrive is their weight range or gain falls below the expected rate.

Doctors will ask for a for a detailed health history, which includes a feeding history, to identify any possible problems. This health history will allow doctors to see whether underfeeding, feeding problems or household stresses are the cause of failure to thrive.

Doctors may order tests such as a complete blood count or urine test to see if there are any underlying medical problems. If the doctor suspects a particular disease or disorder, they may order other tests to check for the condition.

Treatments for failure to thrive or failure to gain weight

The treatment for children who fail to thrive involves ensuring the child receives enough calories to grow and addressing any underlying feeding conditions. This may require help from a specialised care team that may include:

  • A registered dietitian – evaluate the child’s dietary needs
  • Speech therapist – address any sucking or swallowing problems
  • Occupational therapist – help caregivers and children develop successful feeding behaviours
  • Primary care doctor or paediatrician evaluation and treatments
  • Psychologist – see if there are any behavioural issues
  • Social worker – if the family has trouble getting enough food
  • Specialists – cardiologist, neurologist or gastroenterologist to treat any underlying conditions

Children who have failure to thrive can be treated at home in conjunction with regular doctors’ visits. The doctor will probably recommend high-calorie foods and give babies a high-calorie formula. Doctors may recommend foods of a certain texture depending on the child’s feeding habits, spacing out meals to make sure the child is hungry at meal times, avoiding empty calories and other strategies depending on the conditions and family situation.

When to make an appointment with your baby’s doctor

It is important to call your doctor if you notice:

  • A drop in weight gain
  • An abnormal appetite
  • A major change in eating patterns
  • A disinterest in eating

If there is trouble feeding your baby it is important to contact your doctor for help.