Failure to thrive

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Read about failure to thrive, which is when a child does not grow adequately over time. Learn about the causes and management of failure to thrive.

Key points

  • There are a variety of causes for failure to thrive including maternal stress, diluted formula, feeding difficulties or specific health conditions.
  • The best way to diagnose failure to thrive is to carefully measure and plot a baby’s weight, height and head circumference over time and then compare the measurements to the standardized growth charts.
  • Managing failure to thrive includes monitoring and changing your baby's diet and managing mealtime routines.

Failure to thrive occurs when a child does not grow adequately over time. Children with untreated failure to thrive are at risk for having a short stature, behavioural and emotional problems and developmental delays.

Causes of failure to thrive

There are many reasons why a baby might be small for their age; they do not always mean failure to thrive. For example, premature babies and babies who had fetal growth restriction during pregnancy may fall under the fifth percentile on the growth chart. As long as the child is growing at a normal expected rate, they are not considered to be failing to thrive.

Occasionally, breastfed babies gain weight slowly due to inadequate breastmilk supply or problems with breastfeeding technique. A lactation consultant can be very useful in this situation.

A variety of conditions can cause or contribute to failure to thrive. Stress is a frequent factor. For example, a mother who is depressed may have difficulty feeding her baby. The baby may respond to their mother’s depression by becoming withdrawn, which could make them feed less. Other causes of feeding problems and failure to thrive include parents being overly anxious about feeding and trying to coerce a child to eat.

If a baby is given formula that is too dilute, it will affect the amount of calories they take in, and could lead to failure to thrive. Babies who are allergic to cow’s milk may have problems absorbing the nutrients from regular formula. Some children might have specific feeding difficulties such as severe gastroesophageal reflux or birth defects that interfere with their ability to take in enough calories.

Other children may have conditions that prevent them from absorbing nutrients properly. Examples include cystic fibrosis, liver disease and celiac disease and other gastrointestinal problems.

Diagnosing failure to thrive

Failure to thrive is commonly seen by family physicians and paediatricians. A child needs to be diagnosed and treated promptly to prevent the risk of malnutrition and developmental problems. The best way to diagnose failure to thrive is to carefully measure and plot a baby’s weight, height and head circumference over time and then compare the measurements to the standardized growth charts.

World Health Organization weight gain and growth charts for girls

World Health Organization weight gain and growth charts for boys

Your baby’s doctor will use the charts that are recommended for your region.

National Institutes of Health definition of failure to thrive

  • Weight less than the third percentile on a standard growth chart
  • Weight 20 percent below the ideal weight for length


  • A fall-off from a previously established growth curve

On the other hand, many family doctors may diagnose a child as failing to thrive if they fall below the fifth percentile on the weight for age chart, or if their weight for age crosses two percentile lines on the chart. Other family doctors may diagnose failure to thrive if the child falls below the 10th percentile on either the length for age or weight for length charts.

If your child's doctor determines that your child could be failing to thrive, they will assess your child carefully and ask you about the following:

  • diet and feeding behaviours: amount of food and breastmilk/formula consumed per day, how formula is being prepared and whether you are having any feeding battles with your child
  • medical history: your baby’s birth; any recent illnesses or chronic medical conditions; past hospitalizations, injuries or accidents; any gastrointestinal problems
  • past and current medications
  • social history: assessment of who the caregivers are, whether there is any history of neglect and whether there are any stressful events happening in the family
  • family history: assessment of whether there are medical conditions or failure to thrive in the child’s siblings.

The doctor will assess your child to see if there are any developmental problems, since these can arise in children who are failing to thrive.

They will then do a physical examination on your child and assess whether poor nutrition has led to your child’s poor growth. They will also will look for any signs of a genetic disorder or underlying disease that could be impairing your child’s growth or any signs that suggest child abuse or neglect.

The doctor will also observe the interaction between you and your child. For example, they may ask you to feed your baby or bring them a snack at a time that your child is hungry. The doctor will assess your child’s temperament and how you respond to their cues. This information can help your doctor decide the best course of action for treating your child.

Your doctor probably will not order any laboratory tests at this point unless they suspect that your child might have a particular condition or disorder. However, if your child continues to grow poorly despite changes to their diet, the doctor may order some blood or urine tests.

Managing failure to thrive

The first step in managing failure to thrive is to identify the underlying cause and treat it. the next step is to change the child’s diet and feeding behaviours. Babies need three times the amount of calories per kilogram compared with adults. All children with failure to thrive need a high-calorie diet so that they can catch up in their growth and weight gain. They should be followed up by the doctor at least once a month until they not only catch up to the weight they should be but also maintain that weight gain over time.

Monitoring and changing your child's diet

If you are worried about the amount of food that your child is eating, try keeping a three-day diary of their eating patterns. Write down all the foods and the amounts that your child eats over a three-day period. Bring this list to your doctor so they can assess your child’s eating and energy intake.

If your doctor determines that your child is failing to thrive, you will need to increase the amount of calories that your child eats each day. Children with failure to thrive need 50% more than the recommended daily caloric intake based on their expected weight. For example, a healthy baby who is 10 days to one month old needs about 120 calories per kilogram body weight per day, but a baby of the same age who is failing to thrive needs 50 percent more calories, or 180 cal/kg.

Changing a baby's or toddler's diet

If your baby is still breastfeeding or bottle feeding exclusively and has not started eating solids, and your family doctor feels your baby needs to increase the calories they consume, they will advise you how to do this.

If your baby is already eating solids, you can increase their daily calories by adding rice cereal to their other pureed foods. There are also some high-calorie milk drinks available. Ask your doctor whether you should give these to your baby.

There are a number of ways to increase the amount of caloric intake in older babies and toddlers. You can add pleasant-tasting, high-fat foods such as cheese, sour cream and butter to your child’s other foods.

Multivitamins may be helpful to ensure that your child receives the vitamins and minerals they need. Again, however, check with your doctor whether these are suitable for your little one.

Managing mealtime routines

It is natural to be anxious if your child has failure to thrive, but it is important to make sure that you do not force your child to eat. Try to make mealtime pleasant, regularly scheduled and not rushed. Eat with your child. If your child is eating solids, make sure they are comfortable in their high chair and that their head is up. Start with small portions so as not to overwhelm him, and then gradually increase the portion sizes. Encourage them to eat a variety of foods. If they have already been introduced to all four food groups, make sure to include something from each food group at every meal.

If your child is still not gaining enough weight after you take these initial steps, they may need to see a specialist or a team of specialists. A joint approach using doctors, nurses, dietitians, social workers and psychologists may not seem practical at first, but it may be the most helpful solution for your child, especially if they are suffering from an undiagnosed condition or a very challenging social situation. ​

Last updated: October 18th 2009