Diabetes-Related Risks in Pregnancy With One Abnormal Oral Glucose Tolerance Test Result

The accepted cutoffs for gestational diabetes mellitus (GDM) diagnosis using the 100 g oral glucose tolerance test (OGTT) are 2 elevated values according to the criteria of Carpenter and Coustan (C&C). We examined the effect of 1 OGTT abnormal value only according to C&C criteria on pregnancy outcomes.

A population-based retrospective cohort study at a single medical center between July 2013 and September 2021 was conducted. Women were divided into the following groups: (1) without GDM (either normal glucose challenge test or OGTT; N = 14,450), (2) with 1 abnormal OGTT value only according to C&C (fasting glucose 95-104, 1 hour 180-189, 2 hours 155-164, and 3 hours 140-144 mg/dL; N = 661), and (3) with GDM defined as at least 2 abnormal OGTT values according to C&C (N = 904). Only the last group was treated for GDM. The primary outcome was the rate of large for gestational age neonates.

After controlling for background characteristics, 1 abnormal glucose value increased the risk, compared to the control group, for LGA (OR_adj 1.9 95% CI [1.6-2.4]), macrosomia (2.4 [1.9-3.2]), hypertensive disease of pregnancy (1.4 [1.01-1.9]), and shoulder dystocia (3.0 [1.2-7.8]). The risk for LGA and macrosomia was also higher in the 1 abnormal glucose value group compared to the at least 2 abnormal glucose values group (1.4 [1.1-1.9] and 2.1 [1.4-3.1], respectively).

Women with 1 abnormal OGTT value, according to the C&C only, had worse outcome than normoglycemic women or women with GDM. Those women should be considered as having GDM.