Metformin in management of pregnant insulin-independent diabetics

Sixty pregnant "maturity-onset" (insulin-independent), established and gestational, diabetics were treated with Metformin in the second and third trimester after dietary treatment had failed. The incidence of Metformin failure was 53.8% in the established diabetics and 28.6% in the "gestational" diabetics. The 27 Metformin failures were transferred to other therapy, leaving for further analysis 33 patients who received Metformin up till delivery. Two neonatal deaths occurred in this group (1 congenital abnormality and 1 preterm infant) giving a perinatal mortality of 61/1000. This compares with a perinatal mortality of 103/1000 in the Metformin failure group and 105/1000 in a group of insulin-dependent diabetics treated during the same period. Apart from a high incidence of neonatal jaundice requiring phototherapy the infant morbidity in the Metformin group was low. The mothers of 3 infants with congenital abnormalities had received Metformin only during the last trimester of their pregnancy.