Definition of optimal glycaemic control in diabetic pregnancy may still be debated. Measures of glucose control (based on 4-6 daily glucose and frequent HbA1c values) were recorded in two series of diabetic pregnancies; one multicentre study (n = 92, 1979-82), and one study from our own institution (n = 113, 1983-85). The average pregnancy glucose levels were 5.9 mmol/L (third trimester only) and 6.5 mmol/L (all trimesters), respectively. Discriminant analysis (including pregnancy glucose, HbA1c, gestational age, diabetes duration and hypertension) revealed that gestational age only (first series) and gestational age and HbA1c independently of each other (second series) were significantly associated with the occurrence of severe neonatal morbidity present among 30 and 16.8% of the infants, respectively. The overall outcome was favourable. The findings of no perinatal mortality, normal premature delivery rate (8.9%) and a very low rate of severe maternal hypoglycaemia (4.4%) in series two support the feasibility of a strict but individualized management programme.