Gestational glucose tolerance and maternal metabolic profile at 3 years postpartum

Abstract

Objective: To estimate the independent effect of gestational impaired glucose tolerance, defined as a single abnormal oral glucose tolerance test value, on metabolic dysfunction at 3 years postpartum.

Methods: We used multiple linear regression to measure associations between glucose testing during pregnancy and metabolic markers at 3 years postpartum in Project Viva, a prospective cohort study of maternal and infant health. We compared metabolic measures at 3 years postpartum among four groups: normal glucose challenge test (less than 140 mg/dL, n=461); abnormal glucose challenge test but normal glucose tolerance test (n=39); impaired glucose tolerance (a single abnormal glucose tolerance test value, n=21); and gestational diabetes mellitus (n=16).

Results: Adjusting for age, race, parity, parental history of diabetes, and maternal body mass index at 3 years postpartum, we found women with gestational diabetes mellitus had lower adiponectin (11.2 ng/mL compared with 20.7 ng/mL) and higher homeostatic model assessments of insulin resistance (3.1 compared with 1.3) and waist circumference (91.3 cm compared with 86.2 cm) compared with women with impaired glucose tolerance or normal glucose tolerance. Women in both the impaired glucose tolerance and gestational diabetes mellitus groups had lower high-density lipoprotein (gestational diabetes mellitus 44.7 mg/dL; impaired glucose tolerance 45.4/dL compared with normal glucose tolerance 55.8 mg/dL) and higher triglycerides (gestational diabetes mellitus 136.1 mg/dL; impaired glucose tolerance 140.1 mg/dL compared with normal glucose tolerance 78.3) compared with women in the normal glucose tolerance group. We found the highest values for hemoglobin A1c (gestational diabetes mellitus 5.1%, impaired glucose tolerance 5.3%, normal glucose tolerance 5.1%) and high-sensitivity C-reactive protein (gestational diabetes mellitus 1.4 mg/dL, impaired glucose tolerance 2.2 mg/dL, normal glucose tolerance 1.0 mg/dL) among women with impaired glucose tolerance.

Conclusion: Gestational diabetes mellitus and impaired glucose tolerance during pregnancy are associated with persistent metabolic dysfunction at 3 years postpartum, independent of other clinical risk factors.

Figure 1

Flow of patients through the current study, which is a secondary analysis of Project Viva, a longitudinal study of maternal and child health. *Eligibility requirements included singleton gestation, ability to answer questions in English, plans to remain in the area through delivery, and gestational age less than 22 weeks at initial prenatal clinical appointment.

Figure 2

Mean predicted values for a white participant between 35 and less than 40 years of age with a body mass index (BMI) of 26.2 (the study population mean), who has two children and no parental history of diabetes. P-values on graph are for partial F test. The figure shows adverse metabolic markers that differ with gestational diabetes mellitus (GDM) alone (column A), both gestational impaired glucose tolerance and GDM (column B), or gestational impaired glucose tolerance alone (column C). In each graph’s x-axis, A, B, C, and D represent the following groups: Group A, 50-g screen less than 140 mg/dL; B, 50-g screen 140 mg/dL or more with normal oral glucose tolerance test (OGTT); C, 50-g 140 mg/dL or more with one abnormal OGTT value; D, gestational diabetes mellitus (GDM: two or more abnormal OGTT values). Predicted mean, 95% confidence limit of the mean, adjusted for BMI, age, race, parity, and parental history of diabetes mellitus. *P<.05 compared with normal glucose tolerance group.