We describe the maternal characteristics in pregnancy with fetal macrosomia, fetal and maternal complications related to macrosomia, and the risk of impaired glucose tolerance. The study is based on a comparison of maternal and neonatal data in 956 cases of fetal macrosomia (birthweight > or =4000 g) in non-diabetic pregnancy with data in a control group of 6407 mothers with non-macrosomic infants (birthweight 3000-3999 g). The main factors investigated were maternal age, weight, parity, gestosis rate, maternal and fetal birth injuries, maternal oral glucose tolerance test results and umbilical blood insulin levels. Macrosomic infants occurred in 9.1% of all deliveries. Mothers delivering macrosomic infants were significantly older, of higher parity and of greater weight than mothers of the control group. Fetal macrosomia was associated with a higher frequency of gestosis, operative deliveries, birth injuries and postpartum haemorrhages. 26.2% of the mothers had abnormal of oGTT results. The macrosomic infants were more often male and had a significantly higher risk of shoulder dystocia and birth injuries. No essential differences could be observed in the Apgar-scores and umbilical artery pH values. 34% of macrosomic infants had higher insulin levels in umbilical blood.