Vol. 38, No.5, 1995 Printed in U.S.A.Intrauterine growth retardation, or being small for gestational age (SGA), has a life-long impact on a fetus's potential for development and survival. The incidence and relative risk of short stature in children born SGA were studied using a Swedish healthy full-term (37-43 wk of gestation) singleton birth cohort (n = 3650) from Goteborg, followed from birth to final height at about 18 y of age. Most infants, defined as SGA on the basis of a birth length less than -2 standard deviation scores (SDS) below the mean (SGA L infants), showed catch-up growth during the first 6 mo after birth, and by 1 Y only 13.4% of the SGA L infants were below -2 SDS in height. This percentage decreased further during childhood to reach a value of 7.9% at 18 y of age. Although most SGA L infants have catch-up growth in early life, those who do not constitute 21% of short, prepubertal children. At 18 Y of age, 22% of the total short population were short at birth « -2 SDS), whereas when birth weight was used to define SGA, only 14% of the 18-y-old short population were light at birth. SGA L infants were found to have a 7-fold higher risk for short final stature (relative risk, 7.1; 95% confidence interval,