Summary
One hundred ninety-nine gravida with gestational diabetes mellitus (GDM) defined as
“carbohydrate intolerance of varying severity with onset or first recognition during
pregnancy” have been stratified into subgroups on the basis of fasting plasma glucose
and evaluated for further phenotypic and genotypic heterogeneity. A significantly
greater proportion of the women in all our groups were older and heavier than in a
“control” population of 148 consecutive gravida with documented normal oral glucose
tolerance. After correction for age and weight by covariate analysis, absolute insulinopenia
in response to oral glucose could be demonstrated in all GDM groups, although exceptions
were present in each. The incidence of diabetes in the mothers of our patients with
GDM was 8-fold greater than in controls; the incidence in fathers did not deviate
from control patterns. HLA-DR3 and DR4 antigens were more frequently present in GDM
and the increase was statistically significant in blacks. At the time of diagnosis,
cytoplasmic islet cell antibodies (ICA) were significantly more common in GDM associated
with elevated fasting plasma glucose than in controls; the frequency of ICA was 18.4%
(7/38) in women with fasting plasma glucose > 130 mg/dl. Our findings indicate that
GDM entails genotypic as well as phenotypic diversity and may include patients with
slowly-evolving Type I diabetes mellitus, as well as patients with Type II diabetes
mellitus, and women with asymptomatic diabetes which antedated the pregnancy (i.e.
pregestational diabetes mellitus). Appreciation of this heterogeneity should be incorporated
into any evaluation of intervention strategies for women with GDM or into prognoses
concerning their postpartum metabolic status.
Key-Words
Gestational Diabetes Mellitus
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Heterogeneity
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Phenotypic Subgroups
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Insulin Secretion
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HLA Antigens
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Islet Cell Antibodies
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Familial Patterns
