Related Experiment Video
Updated: Oct 16, 2025
Effect of Hyaluronic Acid 35 kDa on an In Vitro Model of Preterm Small Intestinal Injury and Healing Using Enteroid-Derived Monolayers
Published on: July 28, 2022
A systematic review of the definitions and prevalence of feeding intolerance in preterm infants
Charlotte L Weeks1, Luise V Marino2, Mark J Johnson3
1Paediatric Intensive Care Unit, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK.
Insights
Feeding intolerance (FI) in preterm infants lacks a clear definition, impacting research and care. This review found a 27% prevalence of FI, with definitions varying widely and affecting outcomes like time to full enteral feeds.
Area of Science:
- Neonatalogy
- Pediatric Gastroenterology
- Clinical Research Methodology
Background:
- Feeding intolerance (FI) is a common issue in preterm infants within neonatal intensive care units.
- Existing research on feeding methods and comorbidities often focuses on FI, yet a universal definition is lacking.
- This variability in definition complicates research and clinical interpretation.
Purpose of the Study:
- To systematically review and analyze the diverse definitions of feeding intolerance (FI) used in studies involving preterm infants.
- To estimate the prevalence of FI in preterm infants based on the definitions identified.
- To explore how different definitions of FI impact the time to achieve full enteral feeding.
Main Methods:
- A comprehensive systematic literature search was conducted across multiple databases (MEDLINE, Embase, PsycInfo, CINAHL, NHS Evidence, Web of Science).
- Inclusion criteria specified studies on preterm infants in neonatal units with a clear FI definition, involving more than 10 patients, and published in English.
- Studies were categorized into groups based on the specific criteria used to define FI (e.g., gastric residual volume, abdominal distension, gastrointestinal symptoms).
Main Results:
- One hundred studies met the inclusion criteria, revealing significant inconsistency in the definitions of FI.
- Meta-analysis indicated a prevalence of FI ranging from 15% to 30% across different definition groups, with an overall prevalence of 27%.
- The time to achieve full enteral feeds varied substantially (11.3-18.3 days) depending on the definition of FI employed.
Conclusions:
- The definitions of feeding intolerance (FI) in research are highly inconsistent, mirroring issues found in pediatric and adult critical care.
- The overlap in definitions, particularly concerning necrotizing enterocolitis, highlights the complexity of defining FI in preterm infants.
- Further rigorous research is essential to establish a standardized definition of FI for this vulnerable population.
Background & Aims:
Feeding intolerance (FI) is a common phenomenon experienced in preterm infants in neonatal intensive care units, as well as being a focus of many research studies into feeding methods, particularly in relation to comorbidities. There is no widely accepted definition of FI. This systematic review aimed to explore the range of definitions used for FI and provide an estimate of the prevalence amongst preterm infants.
Methods:
Searches were completed on MEDLINE (includes the Cochrane library), Embase, PsycInfo, CINAHL, NHS Evidence and Web of Science. Inclusion criteria; preterm infants in neonatal units, a clear definition of FI, >10 patients and be available in English language. Case reports were excluded.
Results:
One hundred studies were included. Definitions of FI were inconsistent. Studies were grouped according to definition used into: Group A - measuring gastric residual volume (GRV) only; group B - GRV and abdominal distension (AD); group C - GRV, AD and gastrointestinal symptoms (GI) which included any of vomiting, bilious vomiting and blood in stool; group D- GRV and GI; group E - AD and GI; group F - GI only and group G - any other elements used. Meta-analysis demonstrated that prevalence of FI between groups varied from 15 to 30% with an overall prevalence of 27% (95% confidence interval 23-31%). Group A had the highest prevalence. Review of time to full enteral feed was performed (37 studies) which demonstrated a range of 11.3-18.3 days depending on which FI definition used.
Discussion:
Definitions of FI in research are inconsistent, a similar finding to that seen in studies in both paediatric and adult critical care populations. The difficulty of defining FI in the preterm population is the concern regarding necrotising enterocolitis, with some studies using an overlap in their definitions, despite differing pathophysiology and management. Due to the heterogeneity of data obtained in this review regarding definitions used, further robust research is required in order to conclude which elements which should be used to define FI in this population.
Prospero Number:
CRD42019155596. Registered November 2019.
Related Concept Videos
01:15Enteral Nutrition II: Nasointestinal and Gastrostomy Feeding
Nasointestinal Feeding
Nasointestinal feeding involves placing a tube...
01:30Inflammatory Bowel Disease III: Diagnostic Studies and Management I-Nutritional Therapy
Diagnostic studies
A colonoscopy is the definitive screening test, distinguishing ulcerative colitis from other colon diseases with similar symptoms. During a colonoscopy test, inflamed mucosa with exudate ulcerations can be observed, and biopsies are taken to determine the histologic characteristics of the...
01:26Enteral Nutrition I: Orogastric and Nasogastric Feeding
Orogastric (OG) and nasogastric (NG) feeding are two standard methods used for enteral nutrition. Enteral nutrition is often preferred over...
01:23Anatomy of the Intestines
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the...
01:27Parentral Nutrition: Centeral and Peripheral Parental Nutrition
PN can be administered through two primary routes:
1. Central Parenteral Nutrition (CPN):
CPN involves delivering a high concentration of nutrients through a large vein. This is typically achieved using a Peripherally Inserted Central Catheter (PICC) or,...
01:29Intellectual Disability