Poor weight gain (sometimes called faltering weight or failure to thrive) means a child is not gaining weight as expected. It can happen if a child is not taking in enough food, is not able to absorb calories (energy) from the food they're eating, or if their body is using extra calories from an illness or medical condition. Treatment depends on what is stopping the child from gaining weight.

Here's how to care for your child.

• Follow your healthcare provider's instructions for:
  • What to feed your child
  • How much to feed your child
  • How often to feed your child
• For formula-fed babies, mix the formula exactly as directed.
• For breastfed babies:
  • Make sure to feed as often and as long as directed.
  • If you and your baby are having trouble with breastfeeding, ask for a referral to a lactation specialist.
• Take your child for any recommended blood work or testing.
• Schedule and go to all recommended follow-up visits. This will help your child's healthcare provider keep track of your child's growth and development.
• If your healthcare provider recommends it, see a nutritionist or a dietitian (food specialist) for help choosing foods for your child.
• Schedule a visit with a social worker or a psychologist if your healthcare provider recommends it. Sometimes social, emotional, or behavioral issues can play a role in a child's poor weight gain.
• Don't let your child have too many foods with empty calories, such as candy or juice. These can prevent your child from getting the nutrition they need.
• Do not feed your child more than is recommended. Giving too much food or feeding your child too often can sometimes cause vomiting (throwing up), diarrhea, and problems with organs like the heart.

Your child:

• Develops new symptoms such as vomiting, diarrhea, or fever
• Doesn't begin to gain weight as expected
• Loses their appetite
• Is tired a lot or doesn't have the energy to do everyday activities
• Misses developmental milestones such as sitting up, walking, or talking

Your child:

• Is vomiting again and again
• Isn't drinking at all or has signs of dehydration (not enough water in the body), such as a dry or sticky mouth, sunken eyes, less pee or darker pee than usual, little or no tears when crying, or unusual sleepiness

What causes poor weight gain? Poor weight gain happens for many different reasons:

• Some kids do not eat enough. There can be problems with breastfeeding, sometimes formula is measured or mixed incorrectly, and sometimes families have trouble paying for enough food. A child may also have trouble eating food if they have a medical condition (such as a cleft palate or cerebral palsy). In addition, some children are very picky eaters, and others don’t like to eat foods with different textures and tastes.
• Some kids have trouble absorbing enough nutrients and calories. This can happen in children with gastroesophageal reflux (when stomach acid backs up into the esophagus — the tube that connects the stomach to the mouth), chronic (long-lasting) diarrhea, cystic fibrosis (when sticky mucus builds up in the lungs and intestines), liver disease, and celiac disease (when eating gluten causes problems in the small intestine).
• Some kids have conditions that make their body use more calories than normal. This can happen when a child has a medical problem, such as heart disease, an infection, liver disease, or kidney disease.

Why is it important to help my child gain weight? When kids don't gain weight well, they may not grow as tall as they should. Children also need to get enough calories to learn and develop well.