Fetal growth restriction (FGR) can be defined as the failure of the fetus to meet its genetically predetermined growth potential  and is associated with significant fetal and perinatal morbidity and mortality. In addition, there is evidence to suggest a longer-term impact of FGR on childhood neurodevelopmental outcomes  and cardiovascular and metabolic diseases that manifest in adulthood . However, predicting FGR is not straightforward and methods for screening and diagnosis are imprecise. In the UK and USA, ultrasound scans in the second half of pregnancy are not performed routinely but targeted at women considered to be at risk for FGR, where high risk is identified by maternal characteristics (including anthropometry and pre-existing disease), the development of complications, or clinical suspicion based on being ‘small for dates’ on physical examination. For practical purposes, FGR may be suspected if biometric measurements are below a given threshold of the distribution in the population, typically <10th, 5th or 3rd centile for gestational age, or if there is a reduction in growth velocity (‘crossing centiles’) from previous scans . The difficulty with using biometry alone is that it does not differentiate between the growth-restricted fetus affected by placental insufficiency, and the healthy, constitutionally small fetus. Therefore, additional measures may be employed to diagnose placental dysfunction, such as Doppler studies of the fetal and uteroplacental circulation, and analysis of maternal serum biomarkers. At present, the only treatment available for FGR is to expedite delivery, but at preterm gestations this can also can cause harm. However, new genomics-based research could help us better understand the etiology of growth restriction and identify more accurate diagnostic biomarkers or potential therapeutic targets. This chapter will focus on current practice in screening for and intervention in FGR and will also consider new developments and the future of the field.
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