Research in context
Evidence before this study
Fetal growth restriction (FGR) is associated with an increased risk of neurodevelopmental problems in childhood, with lower cognitive test scores and higher rates of impairment across different domains than for children without FGR. We searched PubMed on March 7, 2022, with the search terms “fetal growth restriction” and “neurodevelopment”, with no date or language restrictions. We found that current evidence is primarily based on studies in which singletons with FGR are compared with singletons without FGR, a comparison that is inherently biased by obstetrical, parental, and genetic factors.
Added value of this study
Identical twins discordant for fetal growth are a unique population for studying the actual effect of FGR as they share their genetic make-up, sex, age, and family environment and, apart from the factors that led to discordant growth, had the same in utero conditions and the same gestational age at birth. Our study presents extensive long-term neurodevelopmental follow-up, including age-appropriate cognitive testing and standardised neurological examinations, in a cohort of discordant monochorionic diamniotic twins for whom comprehensive perinatal data are available.
Implications of all the available evidence
Consistent with previous studies, our identical twin study shows a strong association between FGR and neurodevelopmental impairment. Standardised long-term follow-up is essential for the early identification of children at risk of neurodevelopmental impairment. The next step in research on neurodevelopmental outcomes in monochorionic diamniotic twins with selective FGR is to perform MRI studies to identify any changes in structural brain development that underlie the observed functional consequences.