Congenital abnormalities and pregestational diabetes mellitus in pregnancy.

Despite falling perinatal mortality rate, congenital malformation remains the major cause of mortality in infants of mothers with established diabetes. The perinatal mortality rate in this group of infants is 5 times the overall perinatal mortality rate in this hospital. It is well established that pre-pregnancy counselling and maintenance of euglycaemia during the periconception period are the keys to prevention of congenital malformation. We are able to offer pre-pregnancy counselling to 29% of our diabetic mothers who are diagnosed to have pregestational diabetes mellitus only after the 6 weeks postnatal oral glucose tolerance test. Even in the known established diabetes mellitus, 95% of the patients were first seen after the period of organogenesis (> 8 weeks). This could explain our high congenital malformation rate of 15.7%.