Failure to Thrive (Growth Faltering)
When weight gain slows - understanding what it means and what you can do
What Happened
Your child has been identified as having "failure to thrive" (FTT), a term doctors use when a child's weight gain is significantly slower than expected for their age and sex, or when they are crossing downward across percentile lines on the growth chart. This is not a disease - it is a description of a growth pattern that signals something may need attention. The term can feel alarming, but it does not mean you have failed as a parent. Most cases of growth faltering are caused by straightforward issues like feeding difficulties, a picky eating phase, or a recent illness, and they can be addressed with the right support.
Key Facts
- Failure to thrive is defined as weight below the 2nd percentile for age, or a drop across two or more major percentile lines on the growth chart over time.
- It is a sign, not a diagnosis. The important next step is figuring out why growth has slowed.
- The most common cause is inadequate caloric intake - meaning the child is simply not taking in enough calories, often for fixable reasons (feeding technique, food refusal, formula mixing errors, breastfeeding challenges).
- Organic (medical) causes account for fewer than 5% of FTT cases. These include conditions like gastroesophageal reflux, food allergies, celiac disease, or other chronic illnesses.
- Most children with growth faltering catch up with appropriate intervention. Permanent effects are uncommon when the issue is identified and addressed early.
- Growth charts use population data. Some healthy children naturally track along lower percentiles - what matters is the pattern over time, not a single measurement.
What to Expect
- Your pediatrician will review your child's growth chart carefully, looking at the trend over weeks and months rather than any single data point.
- You will likely be asked detailed questions about feeding: what, how much, and how often your child eats. Try not to feel judged - these questions help identify simple fixes.
- Your doctor may order basic labs (blood count, metabolic panel, thyroid function) to rule out underlying medical causes, though often no labs are needed.
- A dietitian or lactation consultant may be recommended to help optimize your child's caloric intake.
- You will likely have more frequent weight checks (every 1–2 weeks initially) to monitor progress. This is a good sign - it means your care team is paying close attention.
When to Worry
- If your child is also losing developmental milestones (not just weight), let your doctor know immediately - this combination requires urgent evaluation.
- If your child is persistently refusing to eat, gagging, or vomiting with most feeds, a feeding evaluation (occupational therapy or speech-language pathology) may be needed.
- If you notice blood in the stool, persistent diarrhea, or significant vomiting, report these to your doctor as they may point to a medical cause.
- If your child seems excessively tired, weak, or has a distended abdomen, seek medical attention the same day.
- If you are feeling overwhelmed, anxious, or blamed, tell your healthcare team. Your mental health matters, and stressed parents need support too.
Your Action Plan
- Keep a food diary for 3–5 days, writing down everything your child eats and drinks, including amounts and times. This gives your doctor valuable data.
- Offer calorie-dense foods: avocado, nut butters (if age-appropriate and no allergy), whole-milk yogurt, cheese, olive oil added to foods, and fortified cereals.
- For formula-fed infants, double-check that formula is being mixed correctly. Even small errors in preparation can significantly affect calorie delivery.
- For breastfed infants, consider a weighted feed with a lactation consultant to assess milk transfer.
- Offer meals and snacks on a consistent schedule (every 2–3 hours for infants, every 3–4 hours for toddlers). Avoid grazing, which can reduce appetite at mealtimes.
- Minimize distractions during meals. Turn off screens, sit together, and make mealtimes calm and positive - avoid pressuring or forcing food.
- Attend all follow-up weight checks. Consistent monitoring is the best way to know whether the plan is working.
- Ask your doctor: "What specific weight gain would you like to see, and over what timeframe?" Having a clear target helps you track progress and reduces anxiety.
Sources
Cole SZ, Lanham JS. Failure to thrive: An update. American Family Physician. 2011;83(7):829-834.
Larson-Nath C, Biank VF. Clinical review of failure to thrive in pediatric patients. Pediatric Annals. 2016;45(2):e46-e49.
WHO Growth Standards Are Recommended for Use in the U.S. for Infants and Children 0 to 2 Years of Age. CDC Growth Charts.