Prevalence

Determining the true prevalence of growth faltering can be difficult due to varying diagnostic criteria and a diversity of populations studied. However, studies indicate that approximately 5% to 10% of infants in primary care settings experience growth faltering, with even higher rates among socioeconomically disadvantaged children and those with chronic medical conditions.¹¹

Although hospitalization related to growth faltering is not common, it represents a considerable fraction of admissions for infants facing nutritional challenges. The prevalence becomes even more pronounced in infants dealing with food insecurity, developmental disabilities, complex medical issues, or adverse social determinants of health.^{Reference Becker, Carney and Corkins12} The variability in reported prevalence is largely attributable to differences in how anthropometric measurements are defined, the age groups examined, and the healthcare environments involved.^{Reference Wright, Parkinson and Pearce3}

Diagnosis of growth faltering

Growth faltering is a significant clinical concern that requires careful evaluation rather than simply being labeled as a diagnosis. It’s critical to recognize that most cases result from a complex interplay of medical, nutritional, developmental, behavioral, and psychosocial factors, rather than a single, isolated cause.^{Reference Cole and Lanham1}

To achieve an accurate diagnosis, a comprehensive history is indispensable. Prior to initiating any laboratory tests or imaging studies, clinicians must diligently collect detailed information in several key areas:^{Reference Cole and Lanham1,Reference Wright, Parkinson and Pearce3}

• – Prenatal, perinatal, and neonatal history: Understanding the early-life factors can reveal important context.

• – Developmental milestones and neurodevelopmental progress: Tracking these can help identify potential delays or concerns.

• – Feeding practices: This includes breastfeeding, formula preparation, feeding frequency, duration of feeds, introduction of complementary foods, and any feeding issues such as vomiting, diarrhea, or aversion.

• – Behavioral characteristics and parent-infant interactions during feeding: Insights into these dynamics can inform interventions.

• – Psychosocial factors: Issues like family structure, caregiver stress, maternal mental health, food insecurity, neglect, or abuse can profoundly impact growth.

• – Family history: Documenting parental stature, growth patterns, and any genetic or chronic illnesses can highlight hereditary factors.

Furthermore, a meticulous nutritional assessment should focus on caloric intake, feeding efficiency, dietary diversity, and mealtime behaviors. Numerous studies have demonstrated that gathering detailed feeding histories can be instrumental in uncovering the root causes of growth faltering.^{Reference Homan2,Reference Kerzner, Milano, MacLean, Berall, Stuart and Chatoor13}

Growth monitoring and growth charts

Accurate anthropometric measurements are vital for diagnosing health conditions in infants. Essential metrics such as weight, length/height, head circumference, and weight-for-length must be plotted on standardized growth charts, with the World Health Organization (WHO) growth standards being the preferred choice for children under two years.¹⁴

Healthcare professionals should take note of the following red flags:

• – Weight-for-age below the 5th percentile.

• – Weight-for-length below the 5th percentile.

• – Body mass index (BMI) that falls below expected norms.

• – A downward crossing of two or more major growth percentile lines over time.

• – A deceleration of growth velocity when compared to age expectations.

Interpreting growth patterns can yield critical diagnostic insights. A decrease in head circumference growth may point to impairments in brain development or neurologic conditions. Maintaining weight while experiencing impaired linear growth may signal an underlying endocrine disorder. When both weight and length decline simultaneously, it typically indicates chronic systemic illness or prolonged undernutrition. Additionally, poor growth coupled with microcephaly should prompt further evaluation for genetic, metabolic, or neurologic disorders.^{Reference Cole and Lanham1}

Specialized growth charts designed for specific genetic syndromes, like Down syndrome, Turner syndrome, and Prader – Willi syndrome, can improve the accuracy of assessments in affected children.

Medical causes of growth faltering

Although inadequate caloric intake remains the most common cause of growth faltering, clinicians should consider a broad range of underlying medical conditions (Table 1).^{Reference Cole and Lanham1–Reference Wright, Parkinson and Pearce3}

Table 1.

Examples of medical conditions associated with failure to thrive, categorized by organ system

Table 1. Long description

A table with two columns and eleven rows. The first column lists organ systems, and the second column lists examples of conditions associated with failure to thrive. Row 1: Organ system, Examples of conditions associated with failure to thrive. Row 2: Neurologic disorders, Increased intracranial pressure; cerebral palsy; neuromuscular disorders; developmental disabilities affecting feeding. Row 3: Cardiovascular disorders, Congenital heart disease; cardiomyopathies; chronic heart failure. Row 4: Respiratory disorders, Cystic fibrosis; chronic lung disease; severe or poorly controlled asthma. Row 5: Gastrointestinal disorders, Celiac disease; gastroesophageal reflux disease (GERD); food protein-induced enterocolitis syndrome (FPIES); malabsorption syndromes; inflammatory bowel disease; intestinal anatomic abnormalities. Row 6: Renal disorders, Chronic kidney disease; renal tubular acidosis; congenital urinary tract abnormalities. Row 7: Endocrine disorders, Hypothyroidism; hyperthyroidism; growth hormone deficiency; diabetes mellitus; adrenal disorders. Row 8: Genetic and metabolic disorders, Down syndrome; Turner syndrome; Russell-Silver syndrome; inborn errors of metabolism; chromosomal abnormalities. Row 9: Infectious diseases, Human immunodeficiency virus (HIV); congenital infections; chronic recurrent infections. Row 10: Hematologic and oncologic disorders, Iron deficiency anemia; chronic hemolytic disorders; malignancies. Row 11: Psychiatric and behavioral disorders, Feeding disorders; avoidant/restrictive food intake disorder (ARFID); severe behavioral feeding difficulties.

The factors contributing to growth faltering are notably different across socioeconomic landscapes and understanding this can drive meaningful change. In low- and middle-income countries, growth faltering is primarily fueled by critical issues such as food insecurity, recurrent infectious diseases, environmental enteric dysfunction, inadequate sanitation, and limited access to maternal and child healthcare. Conversely, in high-income countries, the struggle often lies in inadequate caloric intake, which is frequently linked to feeding difficulties, behavioral feeding disorders, chronic medical conditions, neurodevelopmental disabilities, psychosocial adversity, and social determinants of health.^{Reference Hokken-Koelega, van der Steen and Boguszewski4–Reference Koletzko, Godfrey and Poston6}

Physical examination

A thorough physical examination is an indispensable part of evaluating infants exhibiting growth faltering. This careful assessment can uncover signs pointing to underlying genetic syndromes, chronic systemic diseases, endocrine disorders, or nutritional deficiencies. Even in cases where growth faltering stems mainly from behavioral or environmental causes, often presenting with a normal physical examination, clinicians must remain vigilant for subtle abnormalities that could indicate an organic cause.^{Reference Cole and Lanham1,Reference Romano, van Wynckel and Hulst15}

To ensure an accurate evaluation, measurements of weight, length/height, head circumference, and weight-for-length should be meticulously taken, alongside an analysis of growth velocity over time. It is essential to focus on dysmorphic features, developmental milestones, hydration status, muscle mass, and subcutaneous fat storage. Indicators of moderate to severe malnutrition may manifest as muscle wasting, diminished subcutaneous tissue, pallor, sparse or brittle hair, abdominal distension, delayed wound healing, and visible signs of micronutrient deficiencies, such as rickets, glossitis, or dermatitis.^{11,Reference Becker, Carney and Corkins12}

Examination findings can also serve as critical clues to specific underlying disorders. For example, the presence of cardiac murmurs may indicate congenital heart disease, while hepatosplenomegaly could suggest metabolic or hematologic conditions. Additionally, recurrent respiratory issues might raise suspicion for cystic fibrosis or chronic pulmonary disease.^{Reference Romano, van Wynckel and Hulst15}

Nutritional and environmental exposures experienced during pivotal developmental periods can have lasting impacts on organ function.^{Reference Hokken-Koelega, van der Steen and Boguszewski4–Reference Hanson and Gluckman7} Therefore, a comprehensive clinical assessment must extend beyond traditional anthropometric measurements. It should encompass a thorough evaluation of prenatal and perinatal histories, fetal growth patterns, birth weights, gestational ages, maternal nutritional statuses, pregnancy complications, infant feeding practices, psychosocial stressors, and adverse social determinants of health. This holistic perspective is vital as it uncovers essential insights into developmental risks, allowing clinicians to identify infants who may require closer longitudinal monitoring, even when they seem to achieve short-term nutritional recovery.

Laboratory evaluation

The importance of laboratory testing in assessing growth faltering has transformed significantly over recent years. Current evidence strongly indicates that routine laboratory screening for all infants with growth faltering yields limited diagnostic value and is generally not advisable in the absence of clinical indications.^{Reference Cole and Lanham1,Reference Homan2}

Instead of relying on indiscriminate testing, a more focused approach that utilizes a comprehensive medical history, nutritional assessment, analysis of growth patterns, and the findings from physical examinations can be adopted.^{Reference Wright, Parkinson and Pearce3} Often, detailed clinical evaluations can identify the most probable cause without resorting to extensive laboratory tests. When laboratory investigations are deemed necessary, an initial focused evaluation may include:

• – A complete blood count with iron studies to identify anemia and iron deficiency.

• – Serum electrolytes, blood urea nitrogen, and creatinine to scrutinize renal function and electrolyte balances.

• – Liver function tests when there is a suspicion of hepatic disease.

• – Urinalysis and urine culture if there are concerns regarding renal pathology or recurrent infections.

• – Stool studies for occult blood, reducing substances, fecal fat, or inflammatory markers when malabsorption appears likely.

• – Serologic testing for celiac disease.

• – Sweat chloride testing when cystic fibrosis is a possibility.

Further investigations should be customized based on clinical findings. Thyroid function testing is essential for children exhibiting impaired growth or symptoms indicative of thyroid dysfunction. An endocrine evaluation, including checking for growth hormone deficiency, may be warranted when height velocity shows disproportionate effects. If genetic or metabolic disorders are suspected, options can include chromosomal microarray analysis, targeted genetic testing, metabolic screening, plasma amino acids, urine organic acids, and serum ammonia measurements.^{Reference Wright, Parkinson and Pearce3}

Referral to pediatric subspecialists – such as gastroenterologists, endocrinologists, geneticists, or metabolic specialists – when the initial evaluation suggests complex underlying disorders.

Recognition of growth faltering associated with neglect or abuse

Recognizing growth faltering in infants is crucial, as it may reflect underlying issues such as neglect, maltreatment, or substantial psychosocial challenges. Clinicians must be vigilant when they observe growth impairment, particularly in situations marked by social risk factors or unstable caregiving environments. Current research underscores a range of factors that elevate the risk of neglect-related growth issues. These include poverty, food insecurity, caregiver mental health concerns, substance use disorders, domestic violence, social isolation, intellectual disabilities in caregivers, family instability, and insufficient knowledge of infant nutrition and development.^{Reference Flaherty and Stirling16,Reference Christian17}

Moreover, warning signs such as missed medical appointments, contradictory explanations for poor growth, lack of adequate food, visible signs of poor hygiene, developmental delays, and troubling caregiver-infant interactions should raise red flags.^{Reference Dubowitz18} In these scenarios, conducting a thorough multidisciplinary assessment with social workers and child protection professionals is essential. Healthcare providers must acknowledge that when maltreatment is suspected, they have both an ethical and legal responsibility to comply with local child protection reporting requirements.

Postnatal factors associated with growth faltering

Recent studies powerfully illustrate the complex nature of growth faltering and underscore the critical role of postnatal influences on infant growth. Among the myriad factors contributing to this issue, feeding difficulties stand out as particularly prevalent. Challenges such as ineffective breastfeeding, poor latch, inadequate milk transfer, feeding aversion, prolonged feeding times, oral-motor dysfunction, and inappropriate complementary feeding practices can severely hinder caloric intake.^{Reference Kerzner, Milano, MacLean, Berall, Stuart and Chatoor13} The quality and efficiency of feeding interactions are vital during the initial months of life. Early feeding difficulties – including weak sucking, insufficient coordination of suck-swallow-breathe mechanisms, and inadequate feeding frequency – are associated with slower weight gain and heightened risk of growth faltering. As infants develop, issues related to complementary feeding, food acceptance, and feeding behaviors become increasingly pertinent.^{Reference Wright, Parkinson and Pearce3}

Additionally, maternal and family factors play an essential role. Current evidence indicates that caregiver mental health, especially maternal depression and anxiety, can detrimentally affect both feeding practices and growth outcomes. Infants of caregivers experiencing significant psychological distress are at a greater risk for feeding difficulties, reduced caregiver responsiveness, and impaired weight gain, especially when these issues intersect with socioeconomic disadvantages.^{Reference Black, Hurley and Bengtson19,Reference Vrtikapa, Hoque Urmy and Hoque20}

Recent advancements in telehealth have significantly broadened the scope for evaluating feeding difficulties in the comfort of an infant’s home. Through video consultations and caregiver-recorded smartphone videos of everyday mealtimes, clinicians can effectively observe important details such as feeding behaviors, oral-motor function, caregiver-infant dynamics, feeding duration, positioning, environmental distractions, and behavioral responses – elements that might be overlooked during traditional clinic visits. These remote assessments are often less intrusive and provide critical insights to inform tailored feeding interventions. Moreover, they enhance access to multidisciplinary care for families in underserved or remote areas. It is essential to recognize that while telehealth offers remarkable benefits, it should serve as a complement to thorough in-person clinical evaluations, especially when specific medical or developmental issues require a direct examination.^{Reference Clawson, Kuchinski and Bach21–Reference Goday, Huh and Silverman23}

Management of growth faltering

Effective management of growth faltering starts with accurately identifying and addressing its underlying causes (Fig. 1). Contemporary understanding emphasizes that growth faltering is often the result of multiple factors, including medical, nutritional, developmental, behavioral, and psychosocial influences. Therefore, adopting a comprehensive and family-centered approach is essential, moving beyond the outdated distinction between organic and non-organic causes.^{Reference Cole and Lanham1}

Figure 1.

Flowchart for the evaluation and management of growth faltering, emphasizing the identification and treatment of underlying causes.

Figure 1. Long description

A vertical clinical flowchart titled “Infant with Suspected Growth Faltering.” Step 1, “Confirm Growth Faltering,” includes accurate anthropometry, WHO growth charts, and growth velocity. Step 2, “Comprehensive Clinical Assessment,” includes history, physical examination, feeding assessment, development, and psychosocial and family evaluation. Step 3 asks whether there are clinical features suggesting organic disease. If yes, the pathway leads to targeted laboratory and imaging investigations; if no, it leads to nutritional and feeding evaluation. Both pathways converge at Step 4, “Identify Underlying Etiology,” listing inadequate intake, malabsorption, endocrine/genetic disorders, increased requirements, chronic disease, and feeding or psychosocial disorders. Step 5, “Individualized Management,” includes nutritional rehabilitation, treatment of the underlying disorder, feeding intervention, and multidisciplinary care. Step 6 asks whether there is severe illness or failure of outpatient care. If yes, hospital admission is recommended; if no, outpatient follow-up is recommended. Both pathways lead to Step 7, “Long-Term Monitoring,” comprising growth, neurodevelopment, nutrition, and family support, with the goal of healthy catch-up growth while avoiding excessive adiposity.

To achieve successful outcomes, it is crucial to conduct thorough assessments of nutritional intake, feeding skills, developmental progress, caregiver-infant interactions, family resources, and the broader social determinants of health. While pediatricians play a vital role in diagnosis and treatment, a collaborative effort with a multidisciplinary team can enhance care. This team may consist of a registered dietitian, speech and language therapist, occupational therapist, social worker, psychologist, and relevant pediatric subspecialists who tailor their support according to the infant’s unique clinical needs.^{Reference Kerzner, Milano, MacLean, Berall, Stuart and Chatoor13}

Most infants experiencing growth faltering can be effectively managed in an outpatient setting with diligent monitoring and consistent follow-up. Hospitalization should be reserved for cases, such as severe malnutrition, dehydration, significant electrolyte imbalances, suspected serious medical conditions, failure of intensive outpatient management, concerns surrounding caregiver capacity, suspected neglect or abuse, or instances that necessitate direct observation of feeding practices and caloric intake.^{Reference Homan2,Reference Becker, Carney and Corkins12}

Regular follow-up visits for infants managed in an outpatient setting are essential to ensure an effective response to nutritional rehabilitation and to enable timely adjustments to their management plans. Infants under six months benefit greatly from weekly weight assessments until they establish a steady upward growth trajectory. For older infants, follow-ups every two to four weeks can make a significant difference, depending on how severe the growth faltering is and its underlying causes. These follow-up appointments should include thorough measurements of weight, length/height, and head circumference when appropriate. Monitoring weight-for-length or body mass index (BMI) z-scores, dietary intake, feeding behaviors, caregiver concerns, and developmental progress is also crucial. Achieving stable catch-up growth and normalizing growth velocity allows us to gradually extend follow-up intervals, setting up a clear path for continued health and well-being.^{Reference Kersten, Goday and Abdelhadi24–Reference Gallagher26}

Nutritional rehabilitation

The primary objective of treatment is to restore normal growth velocity by ensuring sufficient intake of calories, protein, vitamins, and minerals while effectively addressing the root causes of malnutrition. Nutritional rehabilitation should be customized for everyone, considering their age, the severity of malnutrition, feeding abilities, and any related medical conditions.^{Reference Hokken-Koelega, van der Steen and Boguszewski4,Reference Nützenadel27}

Feeding interventions

Effective management of feeding difficulties in infants requires a targeted approach based on thorough assessments. Interventions should include refining feeding schedules, enhancing feeding techniques, addressing oral-motor issues, reducing feeding aversion, and adjusting food texture or temperature when necessary.^{Reference Lee, Viegelmann, Dorji and Lim33}

Implementing behavioral feeding strategies has proven to significantly benefit infants struggling with feeding challenges. Caregivers must be encouraged to create structured meal routines and steer clear of coercive feeding practices.^{Reference Kerzner, Milano, MacLean, Berall, Stuart and Chatoor13}

For breastfed infants, increasing the frequency of feeding and providing lactation support can effectively boost caloric intake. In certain situations, temporary supplementation with expressed breast milk or infant formula may be essential. Formula-fed infants could gain from a higher caloric density under the guidance of a healthcare professional. When conventional feeding strategies fail to promote adequate growth, nutritional supplementation with carbohydrates, fats, or specialized formulas should be considered.^{Reference Homan2}

For infants diagnosed with malabsorption disorders, tailored nutritional modifications are necessary. This may involve using medium-chain triglyceride-containing formulas or elemental formulas, depending on the specific medical diagnosis.^{Reference Diéguez Castillo, Sidahi Serrano, Martín Aguilar and De Luis Román34}

Enteral feeding support

When adequate growth through oral feeding is not possible, it’s crucial to consider enteral nutrition as a viable option. For infants in need of short-term nutritional support, nasogastric tube feeding serves as an effective temporary intervention. On the other hand, gastrostomy tube placement is especially beneficial for infants facing chronic feeding challenges, neurological impairments, or those requiring long-term nutritional care.^{Reference Breik, Chaffey and Chan35}

Taking the step to initiate enteral feeding should involve thoughtful assessment of its potential benefits versus procedural risks, alongside family preferences and the infant’s overall prognosis. Evidence demonstrates that, when executed appropriately, enteral feeding significantly enhances nutritional status and promotes healthier growth outcomes in selected pediatric populations.^{Reference Romano, van Wynckel and Hulst15}

Pharmacologic therapy

The routine use of appetite stimulants or growth-promoting medications is not advisable for infants experiencing growth faltering. While certain medications, such as cyproheptadine, may be beneficial for specific populations with underlying conditions, there is insufficient evidence to support their regular use in otherwise healthy infants facing growth challenges.^{Reference Shim, Kim, Choe, Seo and Yang36,Reference Lin, Yen and Tsai37}

Furthermore, growth hormone therapy should only be a consideration in cases of recognized endocrine disorders or approved growth hormone deficiency syndromes. The primary approach to managing growth should emphasize correcting nutritional deficiencies and addressing any underlying medical issues.^{Reference Cole and Lanham1}

Management of underlying medical conditions

When growth issues stem from a specific organic disorder, it’s crucial to target the root cause with appropriate treatment. For instance, initiating a gluten-free diet for those diagnosed with celiac disease, optimizing therapies for congenital heart disease, effectively managing inflammatory bowel disease, correcting hormonal imbalances, or tackling chronic infections can all lead to significant improvements in growth and overall health.^{Reference Mouslih, El Rhazi, Bahra, Lakhdar Idrissi and Hida38}

Child protection considerations

Healthcare providers must remain vigilant when evaluating infants experiencing growth faltering, as signs of neglect or abuse may be present. If there are concerns about insufficient caregiving, food insecurity, medical neglect, or any other types of maltreatment, it is crucial to refer the case to appropriate child protection services in accordance with local regulations.

Engaging multidisciplinary child protection teams early in the process can significantly enhance family support, foster caregiver engagement, and provide critical access to social services, counseling, and community resources that nurture healthy growth and development.^{Reference Christian17}

To effectively manage growth faltering, individualized treatment plans must be developed that meet nutritional needs while also addressing developmental, medical, behavioral, and psychosocial aspects. A coordinated multidisciplinary approach is vital to achieve optimal growth and ensure lasting, positive developmental outcomes.

Nutritional treatment and potential sequelae of growth faltering

Nutritional rehabilitation is a critical component in managing growth faltering, yet it demands meticulous attention to the rate of recovery. Research indicates that aggressive nutritional replenishment in severely malnourished infants can elevate the risk of refeeding syndrome, a serious and potentially life-threatening metabolic condition.^{Reference Becker, Carney and Corkins12,Reference Mehanna, Moledina and Travis39} Refeeding syndrome arises from swift shifts in fluids and electrolytes when nutritional intake is rapidly increased after a period of undernutrition. This syndrome is characterized by significant biochemical abnormalities, including hypophosphatemia, hypokalemia, and hypomagnesemia. Moreover, disturbances in glucose metabolism, thiamine deficiency, and fluid imbalances may occur, leading to severe complications such as cardiac dysfunction, arrhythmias, respiratory failure, neurological issues, and, in extreme cases, death.^{Reference da Silva, Seres and Sabino40} To significantly reduce these risks, it is essential to initiate nutritional rehabilitation gradually, particularly in infants suffering from severe malnutrition or those with extended periods of inadequate intake. Current guidelines advocate for vigilant monitoring of serum phosphate, potassium, magnesium, and glucose levels during the initial refeeding phase, along with the judicious use of supplementation when needed. Incremental increases in caloric intake are crucial, ensuring all micronutrient and essential electrolyte needs are met.^{Reference Friedli, Stanga and Culkin41}

Infants born small for gestational age (SGA) or those with a history of fetal growth restriction (FGR) deserve consideration during their nutritional rehabilitation. While catch-up growth is often desirable and linked to better neurodevelopmental outcomes, excessive weight gain can lead to significant long-term health risks, including insulin resistance, obesity, hypertension, and cardiometabolic disorders.^{Reference Chiavaroli, Castorani, Guidone and Chiarelli42,Reference Embleton, Katz and Ziegler43} The principle of developmental programming suggests that adverse intrauterine conditions can disrupt metabolic pathways, increasing vulnerability to chronic diseases later in life. Thus, it is important for clinicians to promote healthy catch-up growth while avoiding excessive caloric intake that could predispose at-risk infants to serious metabolic complications down the line.^{Reference Cooke, Goulet and Huysentruyt44}

The 2023 International Consensus Guideline on Small for Gestational Age (SGA) emphasizes that the objective of catch-up growth extends beyond achieving normal weight or stature. Optimal catch-up growth should facilitate adequate linear growth, brain development, and neurocognitive maturation while preventing excessive postnatal weight gain, particularly in the form of disproportionate fat mass accumulation. The guideline highlights that rapid weight gain during infancy, particularly when it exceeds increases in lean body mass, is associated with heightened insulin resistance, central adiposity, obesity, and an adverse cardiometabolic profile in later life. Consequently, growth monitoring should prioritize not only anthropometric recovery but also the quality of growth. This approach encourages a balanced increase in lean body mass along with appropriate gains in height and weight. Nutritional strategies must, therefore, promote healthy neurodevelopment without fostering excessive adiposity. Accordingly, the guideline advocates for regular assessments of weight, height, head circumference, and body mass index during infancy, with particular focus on preventing excessive catch-up weight gain while ensuring adequate nutrition to optimize both neurodevelopmental outcomes and long-term metabolic health.^{Reference Hokken-Koelega, van der Steen and Boguszewski4,Reference Norris, Nyati and Murphy-Alford45–Reference Fontaine, Turjeman and Callens47}

Long-term outcomes of growth faltering

As mentioned previously, the long-term effects of growth faltering are significant and well-documented, particularly when it comes to neurodevelopmental, cognitive, behavioral, and physical outcomes. The prognosis related to undernutrition is heavily influenced by its severity and duration.^{Reference Shennon, Wilson and Behling48–Reference Georgieff, Ramel and Cusick50} Nutritional deprivation in infancy occurs during a critical developmental phase, impacting organ maturation through various biological mechanisms.

Nutrients can influence the regulation of synaptic plasticity genes through epigenetic modifications of chromatin. They can affect both histone biology (e.g., methylation and acetylation) and the methylation of DNA CpG islands.^{Reference Cusick and Georgieff51} Early life events, such as nutritional deficiencies and toxic stress, can differentially impact brain development based on their timing, intensity, and duration. Timing is particularly crucial, as the hippocampus and prefrontal cortex develop at different rates. An adverse event affecting neuronal dendritic arborization will more likely harm the hippocampus if it occurs earlier, leading to greater damage compared to the prefrontal cortex.^{Reference Prado, Larson and Cox52}

Current systematic reviews suggest that mild to moderate growth faltering does not necessarily lead to significant drops in intelligence quotient (IQ) when appropriately managed. However, infants suffering from prolonged severe malnutrition remain at a heightened risk for learning difficulties, impaired executive functioning, reduced academic success, and behavioral challenges later in life.^{Reference Prado, Larson and Cox52}

Overall, when nutritional rehabilitation is initiated promptly, physical growth outcomes tend to be favorable, allowing many infants to achieve catch-up growth and attain normal adult height. In contrast, delayed diagnosis or prolonged undernutrition can lead to persistent deficits in height, weight, or body composition – especially among infants facing chronic medical issues or those with severe early-life malnutrition.^{Reference Cole and Lanham1}