Abstract
Background/Objectives: Fetal growth restriction (FGR) describes the situation of a fetus that fails to reach its genetic growth potential. Postnatal catch-up growth represents a central adaptive process, yet its timing and magnitude vary widely and may influence one individual's state of health and later metabolic risk. This study aimed to characterize longitudinal growth trajectories from birth to 10 years in children born at term, affected antenatally by growth restriction, with a particular focus on the influence of sex and FGR severity on catch-up growth. Methods: We conducted a retrospective observational study including 170 term-born children with documented FGR, admitted to a tertiary pediatric center between 2019 and 2023. Anthropometric data (weight, length/height, BMI) at birth, 1, 2, 5, and 10 years were converted to World Health Organization (WHO) age- and sex-adjusted z-scores. Catch-up growth was defined as an increase of >0.67 SD. Participants were stratified by sex and FGR severity (moderate: 10th-3rd percentile; severe: <3rd percentile). Results: Severe FGR infants exhibited significantly lower birth anthropometrics but demonstrated more pronounced early catch-up in weight and length at 1 and 2 years (p < 0.01). By 5 and 10 years, growth trajectories converged between severity groups, with no differences in BMI at any age. Sex influenced absolute anthropometric values but not the probability of achieving catch-up growth. Conclusions: Among term-born FGR infants, severity-but not sex-shapes early postnatal growth. Despite early deficits, most children achieved substantial catch-up, underscoring the need for careful monitoring to support healthy, proportionate growth and mitigate subsequent metabolic risk.