What is the definition of failure to thrive?

Failure to thrive is defined as decelerated or arrested physical growth (height and weight measurements fall below the third or fifth percentile, or a downward change in growth across two major growth percentiles) and is associated with abnormal growth and development. The reason for failure to thrive is inadequate nutrition. Previously, failure to thrive was categorized  as either organic (underlying medical condition) or non-organic (no known medical condition). However, this categorization is considered outdated as the causes and effects of malnutrition are usually intertwined in most children.

Failure to thrive has many different causes, and sometimes more than one cause may contribute to the condition at the same time. If an infant is not offered enough food or is not willing to eat enough food, or vomits repeatedly (such as with severe gastroesophageal reflux), there will not be enough calories to support growth. A child who is unable to absorb enough calories (such as with severe allergies or a medical condition like cystic fibrosis) will also not grow as expected. Any condition that causes a child to need more calories than normally expected may also lead to failure to thrive.

Infants born into families with inadequate support or understanding of infant needs may not provide the right kinds or amounts of food. For example, too much fruit juice, problems breastfeeding, or failure to introduce solids at an appropriate age may lead to too little calories being consumed. Babies and children with developmental delay or problems swallowing may consume too few calories. Conditions such as cystic fibrosis, celiac disease, or severe allergy or intolerance may consume enough food but not be able to absorb it properly. A child with a chronic medical condition, such as congenital heart disease or a genetic syndrome, may need more calories than expected. In severe cases, neglect or abuse may be associated with failure to thrive if food is purposely withheld from a baby. 

The following are the most common symptoms of failure to thrive. However, each child may experience symptoms differently. Symptoms may include:

  • Lack of appropriate weight gain

  • Irritability

  • Easily fatigued

  • Excessive sleepiness

  • Lack of age-appropriate social response (i.e., smile)

  • Does not make vocal sounds

  • Delayed motor development

  • Learning and behavior difficulties later in childhood

The symptoms of failure to thrive may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.

Failure to thrive is usually discovered and diagnosed by the infant's physician. Infants are always weighed and measured when seen by their physicians for well-baby check-ups. The physician initiates a more complete evaluation when the infant's growth, development, and functioning are found to be delayed.

Specific treatment for failure to thrive will be determined by your child's physician based on:

  • Your child's age, overall health, and medical history

  • Extent of your child's symptoms

  • Cause of the condition

  • Your child's tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the condition

  • Your opinion or preference

The individual issues involved in causing failure to thrive are almost always complex. Treatment depends on the cause of the condition and may involve a team of healthcare providers, including social workers, nutritionists, physical therapists, geneticists, and other specialists.

When growing kids don't gain weight as they should, it is called "failure to thrive."

Failure to thrive is not a disease or disorder itself. Rather, it's a sign that a child is undernourished. In general, kids who fail to thrive are not getting enough calories to grow and gain weight in a healthy way. When kids can't gain weight, they also often may not grow as tall as they should.

Kids need to get enough calories to learn and develop well. So kids with failure to thrive might start to walk and talk later than other kids, and can have trouble learning in school.

What Causes Failure to Thrive?

Different things can cause failure to thrive, including:

  • Not enough calories provided. Sometimes a parent or caregiver measures or mixes formula incorrectly, so an infant doesn't get enough calories. Problems with breastfeeding or starting solids also can cause failure to thrive. Some families have trouble affording enough food for their children. And sometimes parents miss their children's hunger cues.
  • The child eats too little. Some children have trouble eating enough food. This might be due to a developmental delay, being a very picky eater, a medical condition that affects swallowing (like cerebral palsy or a cleft palate), or a condition like autism in which kids don't like eating foods with some textures or tastes.
  • Health problems involving the digestive system. Problems with the digestive system can prevent a child from gaining weight. Conditions like gastroesophageal reflux (GER), chronic diarrhea, cystic fibrosis, chronic liver disease, and celiac disease can make it harder for kids to absorb enough nutrients and calories to gain weight.
  • Food intolerance. A food intolerance means the body is sensitive to some foods. For example, milk protein intolerance means the body can't absorb foods such as yogurt and cheese, which could lead to failure to thrive.
  • An ongoing medical condition. Kids with conditions involving the heart, lungs, or endocrine system might need more calories than other kids. It can be hard for some to eat enough.
  • Infections. The body can use up a lot of calories as it fights an infection. And kids who don't feel well might eat less than usual.
  • Metabolic disorders. These are health conditions that make it hard for the body to break down, process, or take energy from food. They also can cause a child to eat poorly or vomit.

Sometimes a mix of things leads to failure to thrive. For instance, if a baby has severe GER and is reluctant to eat, feeding times can be stressful. The baby may be upset and frustrated, and the caregiver might not be able to get the baby to eat enough.

Other times, doctors aren't sure exactly what causes the problem.

How Is Failure to Thrive Diagnosed?

Many babies and kids go through brief periods when they don't gain as much weight as expected. But if a child continues to not gain enough weight or loses weight, doctors try to find out why.

They'll ask for a child's health history, including a feeding history. This helps them see if underfeeding, household stresses, or feeding problems might be causing the problem. A dietitian or other health care professional also may track the calories in a child's diet to make sure the child is getting enough.

Doctors measure a child's weight, length, and head circumference at each well-child checkup and put the results on a growth chart. Children may have failure to thrive if they weigh less than most kids their age or aren't gaining weight as quickly as they should.

Doctors might order tests (such as blood tests or urine tests) to check for medical problems that could affect a child's weight and growth.

How Is Failure to Thrive Treated?

Treating kids who fail to thrive involves making sure they get the calories needed to grow. The care team also will address any causes for poor weight gain they find. A child's care team may include:

  • the primary care doctor
  • a registered dietitian
  • occupational therapists to help with sensory or coordination problems
  • speech therapists to help with any sucking or swallowing problems
  • a social worker if a family has trouble getting enough food
  • psychologists and other mental health professionals for any behavioral issues
  • specialists (such as a cardiologist, neurologist, or gastroenterologist) to treat health conditions that could affect a child's weight

Usually, kids who have failure to thrive can be treated at home. They'll also have regular doctor visits to check on weight gain. Doctors often recommend high-calorie foods and, for babies, a high-calorie formula.

Doctors also might recommend:

  • spacing out meals to make sure children are hungry
  • avoiding "empty" calories like juices and candies
  • offering foods of certain textures if sensory issues are a problem
  • other strategies depending what's causing the failure to thrive

Weight gain takes time, so it might be several months before a child is back in the normal range.

Some children with failure to thrive might need care in a hospital. They'll be fed and watched around the clock for several days (or longer) until they gain some weight. After leaving the hospital, the child will continue treatment at home.

How Can Parents Help?

It can be hard to learn that your child has failure to thrive. No matter what's causing it, there are ways to help and support your child. You can:

  • Follow the advice from your doctor or the dietitian.
  • Take your child to all recommended doctor visits.
  • Call the doctor if your child develops new symptoms, like frequent diarrhea or vomiting.
  • Learn about any medical conditions that the doctor finds in your child.
  • Talk to the doctor or a therapist if you feel stressed or frustrated about problems with feeding your child.