Individuals who meet the Carpenter-Coustan (CC) criteria for untreated glucose intolerance during pregnancy demonstrate impaired β-cell function and substantial metabolic dysfunction at 12 months postpartum, according to study findings published in The Journal of Clinical Endocrinology & Metabolism.
Gestational diabetes mellitus (GDM) is linked to adverse perinatal outcomes and a substantially increased long-term risk for prediabetes and type 2 diabetes (T2D), even among women with milder gestational glucose intolerance. However, the influence of GDM treatment during pregnancy on postpartum metabolic risk remains insufficiently defined.
In this prospective cohort follow-up study, researchers aimed to examine
metabolic profiles and β-cell function during pregnancy and at 12 months postpartum across groups with differing degrees of gestational glucose intolerance. The study included 407 pregnant women aged 18 to 45 years who were randomly assigned to GDM testing with either the CC or the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria. Participants with GDM before 24 weeks were excluded from the study.
[I]mpaired glucose tolerance during pregnancy is a manifestation of underlying metabolic disorders that demand ongoing metabolic attention and surveillance in this patient population to prevent development of T2D.
The researchers compared metabolic characteristics and maternal demographics from pregnancy to 12 months postpartum among individuals with treated GDM, untreated glucose intolerance, and normal glucose tolerance. Generalized linear models were applied across the 3 groups, adjusting for age at oral glucose tolerance test (OGTT), baseline body mass index (BMI), and prior GDM history.
The primary outcome was postpartum glucose metabolism, specifically glucose values and insulin sensitivity, assessed at 12 months postpartum using the Stumvoll Index, Matsuda Index, and Disposition Index.
Of the 407 participants analyzed, 12% had untreated glucose intolerance, 13% had treated GDM (26% diagnosed by CC criteria and 74% by IADPSG criteria), and 75% had normal glucose tolerance.
Among the untreated group, 47% had 1 abnormal 100-g OGTT value, 39% had an isolated elevated glucose challenge test (GCT) of at least 130 mg/dL with normal OGTT, 8% had isolated fasting glucose of 92 to 94 mg/dL, and 6% had at least 2 abnormal OGTT values despite GCT less than 130 mg/dL by CC criteria.
Gestational-to-12-month postpartum weight change did not differ across groups (P =.28), and rates of ever breastfeeding were similar (P =.84), although breastfeeding duration tended to be shorter in the treated GDM group (P =.07). A positive pregnancy test at follow-up occurred in 10.3% of participants, with no group differences (P =.58).
Among those with treated GDM, 77% were managed with dietary modification alone, while 23% required pharmacologic therapy (glyburide, insulin, or metformin).
Study limitations include the absence of data on breastfeeding intensity, reliance on OGTT-derived surrogate measures rather than gold-standard clamp or isotope techniques to assess β-cell function and insulin sensitivity, and limited representation of certain high-risk populations (eg, Asian and Hispanic ethnicities), which may affect generalizability.
The study authors concluded, “[I]mpaired glucose tolerance during pregnancy is a manifestation of underlying metabolic disorders that demand ongoing metabolic attention and surveillance in this patient population to prevent development of T2D.”
