AAP guideline redefines, standardizes care for pediatric faltering weight

A newly published clinical practice guideline from the American Academy of Pediatrics (AAP) and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition provides updated recommendations for the diagnosis and management of faltering weight in children, aiming to standardize care and reduce unnecessary testing.¹

The guideline represents a shift in terminology, diagnostic criteria, and clinical approach for a condition that has long been referred to as failure to thrive (FTT).² The panel states that “this clinical practice guideline panel updates the term failure to thrive to faltering weight and [uses] z score cutoffs rather than percentiles as diagnostic criteria.”

Terminology shift and rationale

The guideline emphasizes that the term FTT has historically been imprecise and potentially stigmatizing. According to the authors, “failure to thrive…has always been more of a descriptive term than a true diagnosis” and lacks a consistent definition.

The updated terminology—faltering weight—was selected through a structured consensus process and aligns with international standards. The panel noted that the previous term carried negative connotations, as “the word failure has led caregivers to feel blamed for their child’s condition.”

This change is intended not only to improve clarity but also to promote more equitable and family-centered care.

Standardized diagnostic criteria

A central contribution of the guideline is the adoption of z score–based criteria for diagnosis. Faltering weight is defined by any of the following:

• Weight-for-length or body mass index (BMI)-for-age less than –1.65 z score
• Weight gain velocity less than –2 z score in children younger than 2 years
• Decline in weight, weight-for-length, or BMI of at least 1 z score

The use of z scores allows for more precise tracking of growth trends across the spectrum of pediatric patients. As described in the guideline, “anthropometric z scores…allow for a more precise description of anthropometric data than percentiles.”

Importantly, the authors emphasize that these criteria are intended as a screening tool and should not be interpreted in isolation. Not all children who meet criteria are undernourished, underscoring the need for clinical judgment.

Multifactorial nature of faltering weight

The guideline highlights that faltering weight is not a single disease but rather a manifestation of underlying factors. The condition is described as “a multifactorial diagnosis that necessitates a systematic application of evidence and a multidisciplinary team–based approach.”

Historically, FTT was categorized as “organic” or “nonorganic,” but the panel notes that this distinction is overly simplistic. The guideline explains that “this approach…is too inflexible for patient management because of the complex interactions between a child’s medical, nutritional, and social issues.” Instead, clinicians are encouraged to assess medical, nutritional, developmental, and social contributors collectively.

Emphasis on clinical evaluation over routine testing

One of the most practice-changing aspects of the guideline is its recommendation to limit routine diagnostic testing. The panel states that “in children without specific signs, symptoms, and findings that would prompt a focal evaluation, the guideline panel recommends against diagnostic testing as part of the initial routine workup.”

Evidence reviewed by the panel found that diagnostic tests rarely identify an underlying cause. In one study cited, only 6.8% of tests contributed to a diagnosis, and in hospitalized cohorts, the yield was even lower.

The guideline further notes that testing may introduce harms, including false positives, increased costs, and reduced equity in care. As stated, diagnostic testing “could result in moderate harm, high costs, reduced health equity, and issues with accessibility and feasibility.”

Instead, the initial evaluation should prioritize the following:

• Detailed history and physical examination
• Feeding and developmental assessment
• Growth measurement and trajectory analysis

Role of endoscopy and targeted testing

Similarly, the guideline recommends against routine endoscopy in the initial evaluation. “The AAP Guideline Panel recommends against endoscopy as part of the initial routine workup,” citing limited benefit and potential procedural risks. Endoscopy and additional testing should be reserved for children with persistent faltering weight or clinical features suggesting a specific underlying condition.

Nutritional and feeding interventions

Management recommendations focus on improving caloric intake and addressing feeding difficulties. The guideline strongly supports increased caloric intake, stating that clinicians should use “increased calories of food/energy rather than no increased calories.”

Oral nutritional supplementation is also recommended, particularly when dietary intake alone is insufficient. However, the panel notes potential limitations, including access and cost barriers.

For children with documented feeding issues, therapy is advised. The guideline recommends “therapy for pediatric feeding disorder rather than no therapy,” reflecting the importance of addressing behavioral and developmental contributors.

Socioeconomic considerations and equity

The guideline takes a nuanced approach to socioeconomic status (SES). While acknowledging that SES influences health outcomes, the panel advises against using it as a diagnostic criterion. Specifically, “the AAP Guideline Panel suggests against using SES as an assigned risk factor when diagnosing faltering weight.”

At the same time, clinicians are encouraged to assess social drivers of health and connect families with resources such as nutrition assistance programs. The guideline underscores that equitable care requires attention to barriers such as food insecurity, access to services, and caregiver mental health.

Implications for pediatric practice

The updated guideline is designed to improve diagnostic accuracy, reduce unnecessary interventions, and support efficient use of health care resources. According to the authors, its implementation is intended to “reduce confusion about diagnostic criteria and improve diagnostic accuracy, decrease overutilization of laboratory testing and imaging…and enhance health care utilization.”

For pediatricians, the recommendations reinforce a shift toward the following:

• Standardized growth assessment using z scores
• Judicious use of diagnostic testing
• Early nutritional and feeding interventions
• Multidisciplinary, family-centered care

Conclusion

This clinical practice guideline represents a significant update in the approach to children with poor weight gain. By replacing outdated terminology, standardizing diagnostic criteria, and emphasizing targeted evaluation and management, the recommendations aim to improve outcomes while minimizing harm. As the guideline notes, early identification and intervention are critical to prevent the long-term consequences of undernutrition and to support healthy growth and development in pediatric patients.

References

1. Kersten HB, Goday PS, Abdelhadi R, et al; American Academy of Pediatrics and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. Clinical practice guideline for diagnosis and management of faltering weight. Pediatrics. Published online March 16, 2026. doi:10.1542/peds.2025-075764
2. Schwartz ID. Failure to thrive: an old nemesis in the new millennium. Pediatr Rev. 2000;21(8):257-264. doi:10.1542/pir.21-8-257