Author Interviews, Diabetes, Diabetes Care, OBGYNE / 11.09.2014
Diabetes in Pregnancy: Lower HbA1c Threshold Improves Detection
MedicalResearch.com Interview With:
Ruth C. E. Hughes
Department of Obstetrics and Gynecology
University of Otago, Christchurch Women’s Hospital
Christchurch, New Zealand
Medical Research: What are the main findings of the study?
Dr. Hughes: The increasing prevalence of undiagnosed type 2 diabetes in women of childbearing age was the main driver behind our study. In clinical practice, we were finding that women with probable undiagnosed diabetes (and pre-diabetes) had already started developing pregnancy complications at the time they were diagnosed with gestational diabetes diagnosis in the late second trimester. It seemed logical to try to identify them in early pregnancy, with the idea that they might benefit from earlier intervention. We thus explored the usefulness of first trimester HbA1c measurements to identify women with unrecognised pre-existing diabetes.
In our study, an HbA1c of 5.9% (41mmol/mol) was the optimal screening threshold for diabetes in early pregnancy. We found that a threshold of 6.5% (48mmol/mol), which is endorsed by the World Health Organization and American Diabetes Association for diagnosing diabetes in pregnancy, would miss almost 50% of women with probable pre-existing diabetes. Of great relevance, women with an early HbA1c of 5.9%-6.4% (41-46mmol/mol) had poorer pregnancy outcomes than those with an HbA1c <5.9% (<41mmol/mol), with a 2.5-3 fold higher relative risk of major congenital anomaly, preeclampsia, shoulder dystocia, and perinatal death. These women were also more likely to deliver before 37 weeks gestation.
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