Evaluation of chlorpropamide in chemical diabetes diagnosed during pregnancy

The intravenous glucose tolerance test (I.V.G.T.T.) was used to diagnose chemical diabetes during pregnancy in 180 women, 50 of whom subsequently received chlorpropamide therapy in a daily dosage of 100 mg; the remainder had no drug therapy.Preliminary work showed the I.V.G.T.T. to be reproducible in the second and third trimesters but not in the puerperium in normal pregnancy. Though intravenous glucose tolerance deteriorates between the second and third trimesters in women with no features of diabetes, a significant improvement occurs after a course of chlorpropamide in a daily dosage of 100 mg during pregnancy in chemical diabetes, but this treatment did not enhance the rate of return to normal glucose tolerance post partum.Plasma glucose and insulin studies showed no evidence of hypoglycaemia or hyperinsulinism in the mother at delivery or in the newborn when chlorpropamide had been used compared with a group receiving no such treatment. In the infants of the chlorpropamide-treated mothers there was a suggestion of an increased rate of glucose disposal in response to a glucose challenge, but no increase in birth weight.There were two fetal deaths in the 50 pregnancies of mothers treated with chlorpropamide, one being due to a mistaken premature delivery and the other to a diaphragmatic hernia. Thus chlorpropamide in a dose of 100 mg a day has been shown to reverse chemical diabetes diagnosed and treated in pregnancy without apparent risk to the fetus.