Early pregnancy high normal HbA1c: a high risk group?

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Perinatal Medicine

Background:

• Glycemic control during pregnancy is crucial for maternal and fetal well-being.
• Hemoglobin A1c (HbA1c) reflects average blood glucose levels over the preceding 2-3 months.
• Defining optimal HbA1c ranges in early pregnancy, particularly in the high-normal spectrum, is important for risk assessment.

Purpose of the Study:

• To investigate the association between high-normal early pregnancy HbA1c levels (35-40 mmol/mol) and adverse perinatal outcomes.
• To compare these outcomes with those in pregnancies with normal HbA1c levels (<35 mmol/mol) in the absence of diabetes.

Main Methods:

• Retrospective chart review of singleton births in the Wellington region (July-December 2019).
• Exclusion of participants with pre-existing diabetes, gestational diabetes, or HbA1c measurements taken at or after 20 weeks.
• Analysis of baseline characteristics, HbA1c levels, and perinatal outcomes, with birth weight analyzed using multiple linear regression.

Main Results:

• The study included 1,067 participants in the normal HbA1c group and 186 in the high-normal HbA1c group.
• No significant difference in birth weight was observed between the high-normal and normal HbA1c groups.
• The high-normal HbA1c group showed significantly lower odds of postpartum hemorrhage and composite maternal adverse outcomes.

Conclusions:

• High-normal early pregnancy HbA1c levels are not associated with an increased risk of adverse perinatal outcomes.
• These findings are specific to pregnant individuals without pre-existing or gestational diabetes.
• The study supports the safety of high-normal HbA1c ranges in early pregnancy within this population.