IUGR puts the fetus at risk of stillbirth, perinatal morbidity and neonatal handicap, yet most instances of IUGR are not recognized. Progress has been made in recent years to monitor the high-risk fetus with intensive biometric and biophysical tests and to determine the appropriate time for intervention. These methods of surveillance are ineffective and inappropriate for population screening, and the main problem remains how to identify the at-risk fetus. Improvement of current performance requires the establishment of appropriate standards by which intrauterine growth can be assessed, and their introduction as part of well-organized screening programmes. We describe a computerized method of predicting the optimal weight for each pregnancy, which is individually adjusted for non-pathological variables such as maternal height, booking weight, ethnic group and parity. The optimal birthweight determines the expected slope or velocity of fetal weight gain. This individualized prediction improves the distinction between constitutional and pathological smallness. Furthermore, preterm weights are measured against a fetal weight norm rather than a birthweight standard that is derived from non-physiological preterm deliveries. The customized growth chart allows screening for growth retardation by determining the growth velocity through serial measurement and plotting of fundal height, backed up as necessary by ultrasound estimation of fetal weight and referral for more intensive surveillance as indicated.