In plain words
HbA1c is a blood test. It shows the share of that has picked up sugar over the past two to three months. Because red blood cells live for months, the test gives an average picture, not a single moment. Clinicians use it to check for diabetes that was already there before pregnancy. It can also help track blood sugar in people who already have diabetes. It is not the same as a home glucose check. Some people have results that are higher or lower than expected for reasons other than sugar, such as anemia. A result is read together with other information. Mothers may see the number on a preconception or early pregnancy lab report.
The deeper version
Glycated hemoglobin (HbA1c) reflects average plasma glucose over roughly the preceding eight to twelve weeks, weighted toward the last month, and is reported as a percentage or in mmol/mol. The diagnostic threshold for diabetes is 6.5 percent (American Diabetes Association Standards of Care, 2025). In pregnancy, HbA1c responds more slowly than a to early glucose change. Red cell turnover and iron status can raise or lower the value, which can mislead interpretation. The differential for an elevated HbA1c before or during pregnancy includes undiagnosed pre-existing type 2 diabetes, and HbA1c is widely used preconception to identify it. The controversy concerns whether HbA1c should replace or supplement the glucose tolerance test for screening, and how to read it in anemic or hemoglobin-variant populations.
Where it comes up
- The preconception visitBefore Pregnancy
- Trimester Zero: preparing your body before pregnancyBefore Pregnancy
- Gestational diabetesPregnancy: Your Body
- Eating with gestational diabetesPregnancy: Eating
What mothers here say about HbA1c
No one has posted under this term yet.
Sources
- American Diabetes Association — Standards of Care in Diabetes: diagnosis and classification of diabetes (2025)