The factors associated with lack of catch-up growth after intrauterine growth retardation (IUGR) are unknown. Objective: To identify these factors by analyzing the clinical features and growth hormone (GH)-insulin-like growth factor I (IGF-I) axis. Methods: 95 patients with height <–3 SD after IUGR were assigned to group 1 without (n = 50) or group 2 with (n = 45) malformations. Twenty-one in group 1 and 19 in group 2 were treated with GH. Results: They were seen at 5.3 ± 0.5 and 4 ± 0.5 year (p = 0.02) with heights at –3.4 ± 0.1 and –3.9 ± 0.2 SD (p = 0.03). Group 1 differed from group 2 in having a lower frequency of consanguinity (2 vs. 28.9%, p < 0.001), and higher frequencies of target heights (26.5 vs. 6.7%, p = 0.02) and mothers’ heights (34.7 vs. 8.9%, p < 0.01) <–2 SD, multiparity (26 vs. 8.9%, p < 0.05), prematurity (36 vs. 15.5%, p < 0.05) and cesarean section birth (42 vs. 17.8%, p = 0.01). The GH-IGF-I axis data and the height increases after 3 years of GH treatment (1.6 ± 0.2 in group 1 and 1.1 ± 0.3 SD in group 2) were similar. Conclusion: The short height of the parents, particularly of the mother, is associated with factors limiting the catch-up growth after IUGR of children without malformations, while the high frequency of consanguinity in those with malformations suggests that transmitted fetal factors affect organogenesis or development.