Intrauterine growth retardation (IUGR) refers to the fetal growth pattern and assumes that at least 2 intrauterine growth assessments are performed, indicating a low growth velocity in the fetus. The term "small for gestational age" (SGA) does not refer to fetal growth but to the size of the infant at birth. Infants with SGA have a low weight and/or length for their gestational age at birth below the 10(th) percentile or -2 SD. Approximately 3-5% of all newborns are born SGA. The etiology of SGA/IUGR is not known. The majority (80-85%) of infants born SGA catch-up within the normal range by 2 years of age. SGA has also been associated with increased prevalence of hypertension and dyslipidaemia at a relatively young age. Most controlled trials have shown a beneficial effect of GH treatment. The growth response seems to be due to the cumulative dose received, parenteral adjusted height standard deviation score (SDS) and bone age pretreatment, baseline overnight peak of GH and IGF-I levels. During GH treatment, children born SGA show a significant increase in fasting levels of insulin and proinsulin and a decrease in insulin sensitivity. Fasting glucose levels significantly increase. All these effects are reversible upon interruption of treatment. However, fasting insulin concentrations as well as glucosylated hemoglobin must be carefully monitored during GH treatment. Total cholesterol, LDL cholesterol and the atherogenic index significantly decrease during GH treatment. An acceleration of bone maturation with GH treatment has been reported even though a gain in height SDS for bone age is demonstrated.