Hyperglycemia and adverse pregnancy outcomes.

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Perinatal Medicine

Background:

• The association between mild maternal hyperglycemia and adverse pregnancy outcomes remains controversial.
• Gestational diabetes mellitus (GDM) is a known risk factor, but risks associated with glucose levels below GDM diagnostic thresholds are less clear.

Purpose of the Study:

• To investigate the association between maternal glucose levels below those diagnostic of diabetes and adverse pregnancy outcomes.
• To determine if there are specific glucose thresholds for increased risk.

Main Methods:

• A large international cohort of 25,505 pregnant women underwent oral glucose-tolerance testing.
• Data were blinded for women with fasting plasma glucose ≤105 mg/dL and 2-hour plasma glucose ≤200 mg/dL.
• Primary outcomes included macrosomia, primary cesarean delivery, neonatal hypoglycemia, and elevated cord-blood C-peptide.

Main Results:

• Strong, continuous associations were found between maternal glucose levels and increased birth weight (ORs 1.38-1.46) and cord-blood C-peptide (ORs 1.37-1.55) per 1 SD increase.
• Elevated glucose levels were also associated with increased odds of primary cesarean delivery (ORs 1.08-1.11) and neonatal hypoglycemia (ORs 1.00-1.13).
• No distinct thresholds for increased risk were identified.

Conclusions:

• Maternal glucose levels below the diagnostic criteria for diabetes are continuously associated with adverse pregnancy outcomes.
• Increased birth weight and cord-blood C-peptide levels are significantly associated with even mild maternal hyperglycemia.
• These findings suggest a need to reconsider glucose level management in pregnancy.