Gestational diabetes mellitus

Abstract

Gestational diabetes mellitus (GDM) is defined as glucose intolerance of various degrees that is first detected during pregnancy. GDM is detected through the screening of pregnant women for clinical risk factors and, among at-risk women, testing for abnormal glucose tolerance that is usually, but not invariably, mild and asymptomatic. GDM appears to result from the same broad spectrum of physiological and genetic abnormalities that characterize diabetes outside of pregnancy. Indeed, women with GDM are at high risk for having or developing diabetes when they are not pregnant. Thus, GDM provides a unique opportunity to study the early pathogenesis of diabetes and to develop interventions to prevent the disease.

Figure 1

Insulin sensitivity-secretion relationships in women with GDM and normal women during the third trimester and remote from pregnancy. Values were measured at the end of 3-hour hyperglycemic clamps (plasma glucose, about 180 mg/dl) (22). Prehepatic insulin secretion rates were calculated from steady-state plasma insulin and C-peptide levels. Insulin sensitivity index was calculated as steady-state glucose infusion rate divided by steady-state plasma insulin concentration. FFM, fat-free mass. Figure reproduced with permission from J. Clin. Endocrinol. Metab. (27). Copyright 2001, The Endocrine Society.

Figure 2

Relationship between pancreatic β cell function and post-challenge glucose levels in women with prior GDM. Data are from 71 nonpregnant Hispanic women who had at least 2 (86% had at least 3) sets of oral and frequently sampled i.v. glucose tolerance tests that were scheduled at 15-month intervals between 15 and 75 months after the index pregnancy (totaling 280 sets of tests). Participants had fasting plasma glucose of less than 140 mg/dl at entry into the study and were followed until that value was exceeded. Disposition index (x axis) is the product of minimal model insulin sensitivity (S_I) and the acute insulin response to i.v. glucose (AIRg), a measure of pancreatic β cell compensation for insulin resistance. The y axis shows glucose values at hour 2 of 75-g OGTTs. Symbols represent mean values for disposition index and corresponding 2-hour glucose values (± 1 SD) in each octile of disposition index. The mean disposition index was 2018 in Hispanic women without a history of GDM (arrow). Figure based on data from ref. .