Maternal diabetes and its cell membrane abnormalities as they affect the foetus: implications for the mother and birth defects.

My brief is to discuss maternal diabetes and its implications for birth defects. The perinatal mortality in Britain has fallen in the last 70 years from 60 per 1000 live births to less than 10. For the baby of the diabetic mother there has been a more dramatic decrease from 249 per thousand live births reported by Peel and Oakley in 1949 to approximately 30 in the Swedish cohort in 1993. However even in countries such as Sweden with one of the lowest figures there is still a three fold higher perinatal mortality for the baby of the diabetic mother compared with the background population. There has been a much less dramatic decrease in the incidence of congenital malformations. Peel and Oakley reported an incidence of 6.9% in 1949, and Hanson from Sweden in 1993 reported only a marginally lower incidence of 6.1%. Recent observations indicate that gestational diabetes (GDM) may be associated with increased incidence of fetal malformation and perinatal mortality. The most frequent and significant morbidity is fetal macrosomia, which in turn is associated with increased risk of birth injuries and asphyxia, (Persson and Hanson. 1998). Detection and definition of congenital malformation vary but in spite of this and the much better maternal diabetic control, congenital malformation today forms a major cause of the perinatal morbidity and mortality.