Fetal growth restriction is defined as failure to reach growth potential and considered one of the major complications of pregnancy. These infants are often, although not universally, small for gestational age (SGA). SGA is defined as a weight less than a specified percentile (usually the 10th percentile). Identification of SGA infants is important because these infants are at increased risk of perinatal morbidity and mortality. Screening for SGA is a challenge for all maternity care providers and current methods of clinical assessment fail to detect many infants that are SGA. Large observational studies suggest that customised growth charts may be better able to differentiate between constitutional and pathologic smallness. Customised charts adjust for physiological variables such as maternal weight and height, ethnicity and parity.