Fetal Growth Restriction, Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder-Connecting the Dots: A Narrative Review.

BACKGROUND/OBJECTIVES: Fetal growth restriction (FGR), formerly known as intrauterine growth retardation (IUGR), is defined as a fetus' failure to reach its genetically predetermined growth potential. FGR has also been implicated in the development of autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD), though strong supporting literature has yet to be published. This study aims to review the existing associations between FGR and autism spectrum disorder or attention-deficit hyperactivity disorder as studied in relevant literature, as well as the mechanisms that provide explanation of that association.

METHODS: We used a combination of the terms 'Autism spectrum disorder' OR 'Attention deficit hyperactivity disorder' OR 'neurodevelopmental disorders' AND 'intrauterine growth retardation (IUGR)' OR 'fetal growth restriction (FGR)' in an electronic search of PubMed/MEDLINE and Scopus databases.

RESULTS: After evaluating the existing literature, we found only a few studies assessed the risk of developing ASD or ADHD in IUGR/FGR children. Neurodevelopmental disorders have generally been linked to very low birth weight, small for gestational age neonates (SGA), prematurity, somatic mutations, and intrauterine caffeine and alcohol exposure. While available evidence supports the notion that IUGR/FGR is related to cognitive impairment and behavioural disorders, the association with ASD or ADHD remains elusive due to the marked variability in the reported outcomes. Few studies have reported a respective higher risk for autism spectrum disorders, yet most of them have failed to identify a statistically significant correlation.

CONCLUSIONS: While autism spectrum disorders and attention deficiency disorder have been generally associated with FGR children, the existing body of literature offers limited evidence to support this theory.