Weight Faltering
The short answer
Weight faltering (previously called "failure to thrive") describes a pattern where a baby's weight gain is significantly slower than expected, causing them to fall below the 2nd percentile for weight or drop across two or more major percentile lines on the growth chart. It is a description of a growth pattern, not a diagnosis. The most common cause in infants is inadequate caloric intake - the baby is simply not getting enough calories, whether from insufficient milk supply, feeding difficulties, or issues with solid food intake. Medical causes such as malabsorption, metabolic conditions, or chronic illness are less common but should be considered.
By Age
What to expect by age
Normal weight gain at this age is approximately 5-7 ounces (150-200 grams) per week. If your baby is gaining significantly less, the most common cause is a feeding issue - whether insufficient breast milk supply, poor latch, inefficient suck, or incorrect formula preparation. A lactation consultant can evaluate breastfeeding technique and milk transfer. Your pediatrician will check for medical causes such as oral abnormalities (tongue tie), reflux, or heart conditions that increase caloric needs.
Expected weight gain slows slightly to about 4-5 ounces (120-150 grams) per week. Weight faltering identified at this age may represent a continuation of early feeding issues or newly developing problems. If your baby seems satisfied after feedings but is not gaining adequately, calorie density of feeds may need to be increased (fortifying breast milk or switching to a higher-calorie formula). A feeding evaluation can identify subtle problems with swallowing or oral motor function.
Weight gain expectations continue to decrease (about 3-4 ounces per week at 6-9 months and 2-3 ounces per week at 9-12 months). As solids are introduced, some babies may not consume enough calories from the combination of milk and food. Picky eating, texture aversion, or gagging on solids can limit caloric intake. If weight faltering persists at this age, your doctor may check for celiac disease, food protein allergies, or other malabsorption conditions that interfere with nutrient absorption.
Toddlers are notoriously unpredictable eaters, and some weight plateau around the transition from baby food to table food is common. However, continued weight faltering in a toddler needs thorough evaluation. Consider whether your toddler is drinking too much milk (displacing solid food calories), has undiagnosed food allergies, or has a behavioral feeding problem. A pediatric dietitian can be extremely helpful in creating a calorie-dense meal plan. Underlying conditions such as celiac disease and inflammatory bowel disease should be considered if basic nutritional interventions do not improve weight gain.
What Should You Do?
When to take action
- Your baby's weight gain slowed slightly around 4-6 months but is still tracking along a consistent, albeit lower, percentile - growth velocity normally decreases with age.
- Your toddler's weight plateaued for a few weeks around 12-15 months when appetite decreased and activity increased - this common transition is usually temporary.
- Your baby dropped from a higher to a lower percentile in the first 3-6 months but is now growing consistently - this "channeling" is normal.
- Your baby was ill for a week and weight gain stalled temporarily but resumed afterward.
- Your baby's weight has crossed down through two or more percentile lines on the growth chart.
- Your baby is below the 2nd percentile for weight and has been consistently low or declining.
- You are concerned your baby is not eating enough - feedings are very short, your baby seems unsatisfied, or diaper output seems low.
- Your baby is losing weight (not just gaining slowly, but actually declining) at any age - urgent medical evaluation is needed.
- Your baby has weight faltering along with persistent vomiting, bloody stools, chronic diarrhea, or signs of dehydration - these suggest a medical cause requiring prompt investigation.
Sources
Related Resources
Related Feeding Concerns
When to Introduce Allergens to Baby
Current guidelines recommend introducing common allergens (peanut, egg, cow's milk products, tree nuts, wheat, soy, fish, shellfish, sesame) starting around 4-6 months when your baby is developmentally ready for solids. The landmark LEAP study showed that early introduction of peanuts (by 4-6 months) reduced peanut allergy risk by 80% in high-risk infants. Do not delay allergens - the old advice to wait until 1-3 years has been reversed because early exposure actually prevents allergies.
I'm Worried My Baby Is Aspirating During Feeds
Aspiration means liquid or food enters the airway instead of the stomach. Occasional coughing during feeds is common and does not usually indicate aspiration. True aspiration is less common and may present as recurrent respiratory infections, a wet or gurgly voice after feeds, or chronic cough. If you are concerned, a swallow study can provide a definitive answer.
Baby Biting Nipple While Nursing
Biting during breastfeeding is a common challenge, especially when babies start teething. It can be startling and painful, but it is almost always a phase that can be managed. Babies cannot actively nurse and bite at the same time because their tongue covers the lower teeth during proper sucking. Biting typically happens at the beginning or end of a feed when the latch is not active. With some gentle strategies, most babies learn quickly that biting ends the feeding session.
My Baby Keeps Choking on Food
First, it's important to distinguish between gagging and choking. Gagging is a normal protective reflex that helps babies learn to eat, while true choking is silent and requires immediate intervention. Most "choking" episodes parents describe are actually gagging, which is common and expected as babies explore new textures. However, if your baby frequently struggles with swallowing or shows signs of true choking, it's worth discussing with your pediatrician.
Baby Choking or Coughing on Milk or Liquids
It is common for babies to occasionally cough, sputter, or have milk come out of their nose during feeding, especially in the early weeks. This usually happens because of a fast milk flow (letdown), an immature swallowing coordination, or feeding in a position that is too reclined. Occasional choking episodes during feeding that resolve quickly are usually not serious. Adjusting feeding position, pacing the feed, and using a slower-flow nipple can help.
Baby Choking vs Gagging - How to Tell the Difference
Gagging is a normal protective reflex that pushes food away from the airway - your baby will cough, sputter, or make retching sounds and will usually be red in the face. Choking is when the airway is partially or fully blocked - your baby may be silent, unable to cry or cough, and may turn blue. Gagging is noisy and resolves on its own. Choking is often silent and requires immediate action. If your baby cannot breathe, cry, or cough, begin infant back blows and chest thrusts immediately.