• Growth
• Neonatology
• Neurodevelopment

The full impact of the intrauterine environment on the long-term health and well-being of the growing child remains incompletely understood. However, it is increasingly clear that poor fetal growth has critical effects on both long-term medical and developmental outcomes. Infants born after intrauterine growth restriction (IUGR) have increased risk for several adult-onset diseases including hypertension, heart disease and diabetes.1 In multiple studies, infants with IUGR have subtle but likely important deficits in cognitive, motor, language and neuropsychiatric outcomes. Importantly, interpretation of the literature on the effects of IUGR is hindered by variation in the definition of growth restriction and therefore wide differences in populations selected for study. Furthermore, the impact of growth on outcomes is likely a ‘U’-shaped continuum, in which poor growth is increasingly detrimental while excessive growth is also harmful. For instance, among more than a thousand Finnish children born at term and followed until 56 months, each SD decrease in birth size was associated with incremental decrements in outcomes across multiple developmental domains.2 In the same cohort, large body size was also associated with adverse outcomes.

A multitude of approaches may be used to characterise the intrauterine growth of a newborn infant. Most commonly, birth weight plotted on standardised growth curves is used to indicate whether the infant suffered from poor fetal growth. However, in addition to birth weight, length, body mass index (BMI), weight for length percentile, midarm circumference (MAC), MAC to head circumference ratio, ponderal index and cephalisation index (head …