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Am Fam Physician. 2016;94(4):295-299

Patient information: See related handout on failure to thrive, written by the author of this article.

Author disclosure: No relevant financial affiliations.

Children with very low weight for age or height and those who do not maintain an appropriate growth pattern may have failure to thrive (FTT), also known as weight faltering. If confirmed by repeated valid measurements, FTT should prompt a search for causes of undernutrition, including neglect, family food insecurity, and underlying medical conditions. Inadequate caloric intake is the most common cause of FTT, but inadequate nutrient absorption or increased metabolism is also possible. Difficulty attaining or maintaining appropriate weight is the first indication of FTT, and sustained undernutrition can impede appropriate height, head circumference, and the development of cognitive skills or immune function in extreme cases. Early identification and management of the issues causing undernutrition are critical. In most cases, an appropriate growth velocity can be established with outpatient management based on proper nutrition and family support. Primary care physicians can effectively treat most children with FTT, and subspecialist consultation or hospitalization is rarely indicated.

Failure to thrive (FTT) is an abnormal pattern of weight gain defined by the lack of sufficient usable nutrition and documented by inadequate weight gain over time. The decrease in the velocity of weight gain results in the child steadily falling off the expected weight curve on growth charts.13 The term weight faltering has been proposed to more appropriately emphasize that problems with appropriate weight gain are the initial and most reliable clinical finding of undernutrition. The term weight faltering is also perceived to be less negative or alarming, and less potentially critical of parents or caretakers.2,4,5

Clinical recommendationEvidence ratingReferencesComments
Valid weight measurements over time, rather than at a single point, are required for the recognition of failure to thrive.C46, 8, 9
World Health Organization growth charts are recommended for children up to two years of age. Centers for Disease Control and Prevention growth charts are recommended for patients two to 20 years of age.C1012 Specialized growth charts can be used in addition to the standard charts for supplemental data collection in children born prematurely or with specific diagnoses, such as Turner syndrome or trisomy 21.
Routine laboratory testing and hospitalization are rarely indicated in the assessment of failure to thrive.C5, 22, 27 Testing should generally be targeted at specific underlying diagnoses that are suspected.

Although problems achieving or sustaining appropriate weight are the predominant manifestations of FTT, ongoing severe malnutrition impairs overall growth, impacting weight first, then length and head circumference. In extreme cases, the development of cognitive skills and appropriate immune function can be impaired, resulting in failure to achieve developmental milestones and normal health.2,5,6


The term FTT should be used as a clinical finding and not as a diagnosis.4,7 Recognition depends on reliable and valid measurements over time; therefore, serial measurements of weight and height must be accurately obtained and charted on an appropriate reference scale (growth chart).46,8,9 The World Health Organization (WHO) growth charts are recommended for patients up to two years of age ( The Centers for Disease Control and Prevention (CDC) growth charts are recommended for patients two to 20 years of age (,12 Specialized growth charts can be used in addition to these standard charts for supplemental data collection in children born prematurely or with specific diagnoses, such as Turner syndrome or trisomy 21.13,14

Although there is no consensus on the definition of childhood FTT, the term is often used for infants and children with weight below the 5th percentile for sex and corrected age.15 Supporting definitions include weight for length below the 5th percentile; body mass index for age below the 5th percentile3; or a sustained decrease in growth velocity, in which weight for age or weight for length/height falls by two major percentiles (percentile markers 95, 90, 75, 50, 25, 10, and 5) over time.15

The prevalence of FTT depends on the population studied and recognition criteria used. In the United States, FTT may occur in up to 10% of children in primary care and in approximately 5% of children who are hospitalized.4,15 The rate of detection depends on the vigilance of individual physicians.16


The most common cause of FTT is inadequate caloric intake. Other causes are inadequate nutrient absorption, increased energy requirements (metabolic demands), or a combination of mechanisms. Specific causes of FTT are listed in Table 1. Risk factors for FTT are traditionally classified as psychosocial or medical (Table 25 ), although FTT is commonly caused by multiple complex factors resulting in inadequate caloric intake. The prevalence of various causes of FTT may differ based on the patient's age and the underlying cause.

Inadequate caloric intake
Gastroesophageal reflux
Inadequate breast milk supply or ineffective latching
Incorrect formula preparation
Mechanical feeding difficulties (e.g., cleft lip or palate)
Neglect or abuse
Poor feeding habits
Poor oral neuromotor coordination
Toxin-induced gastrointestinal upset (e.g., elevated lead levels leading to anorexia, constipation, or abdominal pain)
Inadequate nutrient absorption
Anemia, iron deficiency
Biliary atresia
Celiac disease
Chronic gastrointestinal conditions (e.g., irritable bowel syndrome), infections
Cystic fibrosis
Inborn errors of metabolism
Milk protein allergy
Pancreatic cholestatic conditions
Increased metabolism
Chronic infection (e.g., human immunodeficiency virus infection, AIDS, tuberculosis)
Chronic lung disease of prematurity
Congenital heart disease
Inflammatory conditions (e.g., asthma, inflammatory bowel disease)
Renal failure
Medical conditions
Congenital anomalies (e.g., cerebral palsy, autism, trisomy 21)
Developmental delay
Gastroesophageal reflux
Low birth weight (< 2,500 g [5 lb, 8 oz])*
Poor oral health, dental caries
Prematurity (< 37 weeks' gestation)
Tongue-tie (controversial)
Psychosocial (family) issues
Disordered feeding techniques
Family stressors
Parental or family history of intimate partner abuse or violence (perpetrator or victim)
Poor parenting skills
Postpartum depression
Social isolation of a caretaker
Substance abuse
Unusual health and nutritional beliefs (e.g., restricted diets)

Diagnostic Evaluation

FTT can be confirmed based on a detailed history, physical examination, and growth parameters documented over time. Targeted laboratory and other diagnostic testing should be performed when there is reasonable suspicion of a specific underlying condition.


The key elements of the history include a nutritional evaluation and medical, family, and social histories (Table 3). The nutritional evaluation requires obtaining information about caloric intake and overall nutritional quality from the caregivers who feed the patient. Food diaries can help quantify intake and identify dysfunctional mealtimes, grazing habits, lack of a routine or schedule, distractions during feeding, and inappropriate caretaker responses to the child's feeding behaviors.13,17,18 A common problem in toddlers is excessive intake of nutrition-poor liquids, such as “fruit” juice that is predominantly flavored sugar water, that produce satiety before nutritious foods can be consumed.19

Feeding history
EnvironmentRegular feeding routine at home and day care
Family eating patternsCultural or religious food restrictions; immigrant families may be unfamiliar with the nutritional quality of local foods
Preparation of foodFormula mixing technique, frequency of feedings, use of baby foods and table foods
ResourcesUse of Women, Infants, and Children program, social workers, and home health visits; access to food supplies
Personal medical history
Medical conditionsAtopy,* food allergies, gastroesophageal reflux, urinary tract infections, renal tubular acidosis
Family medical history
Gastrointestinal conditionsCeliac disease, inflammatory bowel disease, cystic fibrosis
Parental childhood nutritionParental malnourishment
Parental height, parental age at pubertyGenetic short stature, constitutional growth delay
Psychiatric illness, substance abuseAffecting caretaker function
Social history
Living conditionsSafety and comfort, ability of parents to provide appropriate nutrition
Parent-child relationshipPoor parenting skills, lack of attachment
Primary caregiversParents, family members, foster family
StressorsFinancial and emotional support for child and family
Review of systems
Illness (respiratory infections, gastroenteritis, fevers, fussiness or irritability), recurrent illness, travelEmergency department and office visits, hospitalizations, parasite exposure, exposure to endemic illnesses (e.g., tuberculosis)

A brief developmental evaluation using any standard validated questionnaire helps to identify patients with potential developmental abnormalities contributing to FTT. Abnormal development may be an early indicator of an underlying medical condition, such as a neuromuscular disorder or a psychosocial problem, such as neglect, that can contribute to or exacerbate FTT. Also, children with FTT have a higher incidence of developmental delay.20 The assessment provides a baseline for ongoing monitoring of development that may be impacted by severe nutritional compromise. One example of a free tool for monitoring development is the Rourke Baby Record from Canada (available at


The goals of the physical examination are identification of any chronic or acute illness, recognition of dysmorphology suggesting a genetic condition, assessment for normal development, and quantification of the degree of undernutrition. Table 4 includes key physical examination findings in children with FTT. Underlying medical problems need to be appropriately treated. The physical condition of the child and any comorbid conditions determine the subsequent steps in management.

FindingPotential underlying causes
Dysmorphic appearanceGenetic abnormality, undiagnosed syndrome
EdemaRenal, liver disease
Hair color/texture changeZinc deficiency
Heart murmurAnatomic cardiac defect
HepatomegalyInfection, chronic illness, malnutrition
Mental status changeCerebral palsy, poor social bonding
Poor parent-child interactionDepression, social stress
Rash, skin changes, bruisingHuman immunodeficiency virus infection, cow's milk allergy, abuse
Respiratory compromiseCystic fibrosis
WastingCerebral palsy, cancer


No standard set of laboratory tests is recommended for FTT. A thorough history and physical examination may be all that is indicated to initiate treatment.5,22 If used, reasonable initial laboratory testing includes complete blood count, urinalysis, electrolyte measurement, thyroid tests, and testing for celiac disease. Specific testing for cystic fibrosis, food allergies, human immunodeficiency virus infection, or tuberculosis may be indicated depending on the presentation. Additional testing should be specific for a suspected diagnosis based on history and physical examination findings.


The goal of treatment is to establish optimal growth velocity while supporting the family in the plan of care. Prolonged malnutrition can negatively impact growth potential and cognitive development.1,2 Early intervention that results in corrected growth parameters is believed to lead to positive developmental outcomes, but further studies are needed.2,16 Primary care physicians can treat most patients with FTT in the outpatient setting. If usual treatment is insufficient, support from additional health care professionals, such as a dietitian, social worker, dentist, or lactation specialist, may be helpful.

Attention to several specific health factors is needed to ensure overall treatment success. Dental caries should be treated. Sleep disorders or problems should be identified and addressed because poor sleep can contribute to poor activity and behavior, and subsequently poor nutrition.23 Parents of children who are being treated for FTT should be counseled on sick care management and the importance of encouraging a regular balanced diet. Home nursing visits can complement clinic evaluations, especially for families who have difficulty with transportation or getting time off of work. Families with problems obtaining nutritious foods (food insecurity) should be provided with social work support or other community resources, such as the Women, Infants, and Children program.

Pharmacotherapy, such as cyproheptadine or megestrol (Megace), has been studied and may be helpful for specific populations with significant underlying diseases (e.g., cystic fibrosis, chronic renal disease) or in patients undergoing cancer treatment.2426 However, appetite stimulants are not recommended for most patients with FTT.

Catch-up growth will occur when the child gains at two to three times the average rate per age5 (eTable A). eTable B shows one method for calculating catch-up calorie needs. For infants, an evaluation of breastfeeding and lactation or an adjustment in formula concentration is indicated if inadequate caloric intake is responsible for FTT. eTable C shows formula recipes for increasing calories. Without performing complicated calculations, most infants will tolerate increasing formula concentration from 19 to 24 kcal per oz. Caregivers of toddlers and older children should be counseled on nutrient-rich, healthy food choices, ideally provided in three meals and three snacks per day.5

Age (months)Median weight gain (grams per day)
0 to 326 to 31
3 to 617 to 18
6 to 912 to 13
9 to 129
12 and older7 to 9
AgeKcal per kg per day
0 to 6 months108
6 to 12 months98
1 to 3 years102
Calories (kcal) per ozWater (oz)Scoops of formula powderFinal volume (oz)
19 (per standard product instructions)424.5
20 (per standard product instructions)424.5

Follow-up visits ranging from weekly to every few months are used to document weight, and the plan should be adjusted as the child progresses. These frequent visits provide opportunities to ensure that immunizations are up to date to support the child's immune system. Infants need more frequent follow-up than older children. Daily weight checks at home or in the office are discouraged. Weight change is better averaged over intervals of a few days to weeks until normal growth velocity is achieved. When weight checks occur over a short interval (e.g., during a hospital stay) they should occur on the same scale and at the same time of day, before feedings and with consistent dress. When weight is checked in the office, a routinely calibrated scale and consistent technique should be used.

Hospitalization is rarely indicated5,22,27 but can facilitate subspecialist involvement and provide observed structured feeding evaluations. Table 5 includes indications for hospitalization. Hospitalization should be considered if the child is at severe health risk. Hospitalization or subspecialist referral should be considered if intensive outpatient treatment is ineffective after three to four months, or sooner for newborns.3 Children with complex medical, developmental, and social problems may show weight gain in the hospital setting because of the support of the highly trained multidisciplinary medical staff. Weight gain in the hospital does not necessarily confirm inadequate feeding or care by the family as the cause of FTT. Successful hospitalization requires careful integration of the child's usual caretakers in the patient's care and discharge planning.

Extreme parental impairment or anxiety
Extremely poor parent-child interaction
Need for precise documentation of nutritional intake
Outpatient treatment failure
Psychosocial factors that put the child's safety at risk
Serious underlying illness or medical problem
Severe malnutrition or dehydration

Accelerated growth must be maintained for four to nine months to resolve FTT and achieve appropriate weight for height. Weight for height measurements above the 10th percentile with normal weight gain on two evaluations at least one month apart are reassuring for successful treatment.5 Relapses are possible, and continued observation is needed after successful completion of the frequent visit schedule. The risk of relapse is increased if the underlying etiology is not adequately addressed. Once FTT is resolved, patients require standard well visits with emphasis on monitoring for nutrition and growth.9,16


Routine health surveillance visits in early childhood give primary care physicians opportunities to counsel and educate families on nutrition. Risk factors for FTT can also be identified and addressed. The American Academy of Pediatrics' Bright Futures series has helpful nutrition information for children in different age groups.28

Data Sources: A PubMed search was completed using the key terms pediatric failure to thrive and pediatric weight faltering. The search included meta analyses, reviews, randomized controlled trials, and clinical trials. Additional searches included UpToDate, Essential Evidence Plus, the Cochrane database, and evidence-based guidelines from the National Guideline Clearinghouse, American Academy of Pediatrics, and Centers for Disease Control and Prevention. Search dates: July and December 2015.

The author thanks Drs. Anne Walling, Brian M. Pate, Kari Harris, and Deborah Kroeker for their review and helpful comments during the preparation of the manuscript.

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