To assess the effects of gestational diabetes mellitus (GDM) on intermediary metabolism in late pregnancy, circulating levels of glucose, FFA, triglycerides, cholesterol, and individual amino acids were monitored for 24 h while subjects received a liquid formula diet (containing 2110 cal and 275 g carbohydrate) in three equal feedings at 0800, 1300, and 1800. Attempts were made to distinguish between varying degrees of severity of gestational diabetes by subdividing the population into those with fasting plasma glucose within the normal range for pregnancy, i.e., below 105 mg/dl (GDM < 105), and those with fasting plasma glucose of 105 mg/dl or greater (GDM ^ 105). Both groups were compared with pregnant women with normal carbohydrate metabolism (NM). The diurnal profiles indicated that premeal, postprandial averages, and integrated 24-h values for plasma glucose were consistently higher in GDM ^ 105 than in GDM < 105; both GDM groups uniformly exceeded the values in NM. Plasma FFA tended to be higher in all GDM, with maximal increments occurring in the early hours before breakfast and assuming greatest significance in GDM > 105. The elevations in circulating cholesterol that occur in pregnancy were not significantly different at any time point in NM, GDM < 105, and GDM ^ 105. However, the increases in plasma triglycerides were greater in GDM < 105 and GDM > 105 than in NM and most marked in GDM > 105. Diurnal profiles for a number of individual amino acids (phenylalanine, tyrosine, alanine, serine, proline) were not affected by gestational diabetes. However, certain other amino acids, particularly the branched chain (leucine, isoleucine, valine), tended to be elevated in subjects with GDM and to the most significant extent in GDM > 105. Although the GDM subjects tended to be heavier than the NM, the progressively more pronounced metabolic abnormalities in GDM > 105 than in GDM < 105 would suggest that relative insulinopenia rather than obesity contributed to the differences. Our findings indicate that gestational diabetes is attended by disturbances of varying degrees in all major classes of insulin-dependent foodstuffs and must be viewed as a disorder of multiple fuels, DIABETES CARE 3. -402-409, MAY-JUNE 1980. G estational diabetes mellitus (GDM) is usually ture medium in which the conceptus develops. 1 " 3 In keeping viewed as a minor abnormality in glucose ho-with this formulation it was reasoned that disturbances in meostasis. The present studies represent the first multiple aspects of maternal fuel economy would serve to enefforts to quantify the magnitude of the carbohy-hance the pathophysiologic implications of GDM for the drate abnormalities and to include amino acids, triglycerides, fetus. and cholesterol in the concurrent assessment of other fuels.Our efforts have indicated that even the mildest forms of Blood samples have been secured "around-the-clock" for 24 GDM are attended by demonstrable deviations from normal h in mothers with normal carbohydrate metabolism and in the circulating levels of e...

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We have examined gravida with gestational diabetes mellitus (GDM), as defined by the National Diabetes Data Group (Diabetes 1979; 28:1039), for phenotypic and genotypic heterogeneity. Fasting plasma glucose (FPG) at diagnosis was used for further stratification of GDM according to putative metabolic severity into class A1 (FPG less than 105 mg/dl [N = 129]), class A2 (FPG 105-129 mg/dl [N = 47]), and class B1 (FPG greater than or equal to 130 mg/dl [N = 23]). All GDM classes tended to be older and heavier than consecutive gravida with documented normal glucose tolerance (controls, N = 148). Subdivision into "lean" and "obese" indicated that plasma immunoreactive insulin (IRI) was greater after overnight fast in the obese of all groups except B1. However, absolute increases in IRI above fasting levels in response to glucose during OGTT were significantly enhanced by obesity only in class A2 gravida. Adjustment for the effects of age and weight by covariate analysis indicated that the IRI response to glycemic stimulation is usually attenuated in all forms of GDM. Mean values for increases in IRI above fasting values during the first 15 min and IRI increments relative to the increases in plasma glucose throughout the 180-min OGTT were below control values in all GDM groups and progressively so, i.e., A1 less than A2 less than B1. The absolute insulinopenia was not invariable; a small number of gravida from all GDM groups displayed well-preserved IRI responses to oral glucose. Genotypic evaluation of the GDM population disclosed an increased occurrence of "markers" known to be associated with type I diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)