A prospective study of 70 singleton pregnancies at high risk for intrauterine growth retardation (IUGR) was undertaken to determine 1) the differences in intrauterine growth patterns; 2) the diagnostic accuracy of obstetric techniques; and 3) the frequencies of perinatal complications. Thirty infants displayed signs of IUGR. Although only 14 infants had low birth weights, these 14, as well as the remaining 16 infants under study, displayed many other features of growth abnormalities, including a low ponderal index, short stature, and small head circumference. These data demonstrate various patterns of IUGR. Although the perinatal complications occurred primarily in the low-birth-weight group, the major growth abnormalities observed in the non-low-birth-weight group demonstrate the need for additional short- and long-term follow-up studies in both groups.