France: Glycated Haemoglobin (HbA1c) and Pregnancy Complications

A recent study reveals that glycated haemoglobin (HbA1c) at gestational diabetes diagnosis may identify women at risk for pregnancy complications.

Findings of the study, published in the journal Diabetes & Metabolism, suggest that HbA1c at the time of testing for gestational diabetes may be a useful pragmatic tool for identifying women at risk. This would be helpful for identifying and applying preventative treatment for women at increased risk.

Prior to the study, it was not clear whether HbA1c has utility in predicting adverse outcomes in GDM. Anne Vambergue, University of Lille, Lille, France, and the team therefore aimed to examine the predictive value of HbA1c at GDM diagnosis with adverse pregnancy outcomes in a cohort study.

The study included 4,383 women with GDM between 2011 and 2018. The association of HbA1c with pregnancy outcomes was assessed before and after adjustment for predefined risk factors of GDM. The researchers examined these associations considering HbA1c as categorical variables using five pre-specified HbA1c classes and as a continuous variable.

Key Findings

• An HbA1c ≥ 5.6% (38 mmol/mol) identified women with a greater risk for macrosomia: odds ratio (OR) = 2.12 for HbA1c = 5.6-5.9% and 2.06 for HbA1c > 5.9% versus HbA1c ≤ 4.5% (26 mmol/mol).
• HbA1c ≥ 5.6% (38 mmol/mol) was associated with a greater risk for caesarean: 1.64 for HbA1c = 5.6-5.9% and 1.58 for HbA1c > 5.9% (41 mmol/mol) versus HbA1c ≤ 4.5% (26 mmol/mol).
• Using HbA1c ≤ 4.5% (26 mmol/mol) as a reference category, HbA1c > 5.9% (41 mmol/mol) increased the OR of preterm delivery to 3.33.
• HbA1c remained significant for Adverse Pregnancy Outcome Composite after adjustment.

"The findings suggest that a single HbA1c reading may be a useful pragmatic tool to identify women at risk," wrote the authors. "Such identification may be a useful guide for identifying and applying preventative treatment for women at increased risk."

Reference

The study titled, "HbA1c at the time of testing for gestational diabetes identifies women at risk for pregnancy complications," was published in the journal Diabetes & Metabolism.

DOI: https://doi.org/10.1016/j.diabet.2021.101313