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.
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:
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.