The Impact of Fecal Microbiota Transplantation on Gastrointestinal and Behavioral Symptoms in Children and Adolescents with Autism Spectrum Disorder: A Systematic Review.

This review looked at whether fecal microbiota transplantation (transferring healthy gut bacteria) could help with stomach problems and autism symptoms in children. While some studies showed promise, the better-quality research gave mixed results. The researchers say we need more high-quality studies with consistent methods before we can know if this treatment really works for autistic children.

This systematic review examined fecal microbiota transplantation (FMT) as a potential treatment for gastrointestinal and behavioral symptoms in children and adolescents with autism spectrum disorder. The review included nine studies (two randomized controlled trials and seven before-and-after studies) published through October 2024. While all before-and-after studies reported improvements in both GI and ASD-related symptoms, the randomized controlled trials showed inconsistent results. The before-and-after studies had high risk of bias, whereas the RCTs demonstrated low risk of bias.

The authors concluded that methodological limitations and contradictory findings make it difficult to draw clear conclusions about FMT effectiveness, highlighting the need for standardized protocols in future rigorous trials.

Current evidence does not support routine clinical use of FMT for autism-related symptoms. The inconsistent results from higher-quality studies and methodological concerns suggest more rigorous, standardized trials are needed before FMT can be recommended as an evidence-based intervention for children with autism spectrum disorder.

Methodological limitations in included studies, high risk of bias in before-and-after studies, inconsistent findings between study types, variations in intervention protocols, and small number of high-quality RCTs limit the ability to draw definitive conclusions about FMT effectiveness.

: Gastrointestinal (GI) symptoms, often reported by individuals with autism spectrum disorders (ASD), may impair functionality and exacerbate behavioral symptoms. Gut dysbiosis has been identified as a potential environmental factor influencing these symptoms through gut-brain axis dysregulation. Fecal microbiota transplantation (FMT) is a promising therapeutic strategy with potential to alleviate symptoms. This review systematically evaluates the efficacy and safety of FMT in GI and ASD-related symptoms.: This systematic review followed PRISMA 2020 guidelines and was registered in PROSPERO.

The review included clinical trials on FMT in children and adolescents with ASD, published up to October 2024. The bias assessments were performed using Cochrane tools. Outcomes focused on changes in GI and ASD-related symptoms using scales selected by the authors.: This systematic review included two RCTs and seven before-and-after studies. Improvements in GI and ASD-related outcomes were reported in all before-and-after studies, whereas the results of RCTs were inconsistent.

The before-and-after studies showed a high risk of bias, while the RCTs demonstrated a low risk.: Although many studies have been conducted, the methodological limitations of some and contradictory findings of others make it difficult to draw clear conclusions about the effectiveness of FMT in children with ASD. Variations in intervention protocols underscore the importance of establishing standardized FMT procedures in future rigorously designed trials.