Diurnal variations in blood intermediary metabolites in mild gestational diabetic patients and the effect of a carbohydrate-restricted diet.

Twenty-four hour metabolic profiles were performed in the third trimester of pregnancy in seven non-diabetic women (group A) and in two groups of mild gestational diabetics, at diagnosis (group B, seven patients) and after treatment with a 150-g carbohydrate diet (group C, seven patients). Mean 24-h blood metabolite levels (+/- SD) in groups A, B and C were: glucose: 4.65 +/- 0.82, 5.35 +/- 3.06 and 5.40 +/- 1.7 mmol/l; alanine: 1.05 +/- 0.18, 1.14 +/- 0.42 and 0.78 +/- 0.22 mmol/l; alanine: 0.31 +/- 0.03, 0.31 +/- 0.10 and 0.27 +/-0.07 mmol/l; ketone bodies: 0.11 +/- 0.04, 0.19 +/- 0.05 and 0.26 +/- 0.15 mmol/l. Glucose levels were not significantly different between the groups. Ketone body levels were elevated in the diabetics prior to treatment (p less than 0.01) and rose higher on diet. Lactate levels were reduced on the diet (0.05 less than p less than 0.10). Abnormalities in the concentrations of total blood ketone body levels in gestational diabetics may be detrimental to fetal development and therapy should be designed to minimise changes in intermediary metabolites.