Seventy-one pregnancies complicated by gestational diabetes and 100 healthy pregnancies were monitored on two occasions (between 27th-32nd and 33rd-36th week of gestation) by behavioural state analysis (1F coincidence; 2F coincidence) and umbilical artery Doppler velocimetry (UA) (Resistance Index, RI). The purpose of our study was to determine if the development of behavioural states and Doppler velocimetry: (1) differ between normal and gestational diabetic cases; (2) in gestational diabetic cases, are they related to the degree of abnormality of the maternal oral glucose tolerance test (OGTT)?; and (3) are they predictors of perinatal outcome? (i.e. emergency caesarean section; low Apgar scores; respiratory distress syndrome; neonatal hypoglycaemia and neurological abnormality in the neonate and/or at 4 months of age). Our findings suggest that: (1) results on behavioral state development and Doppler velocimetry were significantly different in gestational diabetic cases; (2) infants of women with gestational diabetes who are neurologically abnormal during the newborn period, had a poor development of coincidence 2F during fetal life and had neonatal hypoglycaemia more often than infants with a normal neurological outcome; (3) in cases with abnormal neurological outcome, the maternal diabetes was more severe than in those cases with normal outcome.