Study of Correlation of HbA1c with Anemia in Pregnancy

HbA1c is a biochemical marker to evaluate hyperglycemia status in past 2-3 months. HbA1c ≥ 6.5% is diagnostic criteria for diabetes mellitus according to the American Diabetes Association. Recent studies suggest that anemia alters HbA1c levels, but results are conflicting. This study was planned to understand utility of HbA1c in relation to hemoglobin (Hb) for the diagnosis of gestational diabetes mellitus (GDM) and also to understand if HbA1c can be used as a screening modality for diagnosis of GDM in countries with higher anemia prevalence.

An observational study was conducted on 193 pregnant women of < 16-week gestation attending antenatal OPD of Department of Obstetrics and Gynecology, KGMU, Lucknow, over a period of one year. Blood glucose levels 2 h after ingestion of 75 gm glucose load irrespective of last meal (DIPSI criterion) were determined at 3 antenatal visits along with HbA1c and Hb level and categorized into diabetic and nondiabetic and anemic and non-anemic group. These patients were followed up till delivery to look for various maternal and neonatal outcomes.

A total 416 tests were done for hemoglobin and HbA1c in 193 women. Prevalence of GDM was 32.1%. Cutoff level of HbA1c was 4.8% in our study which also varied according to gestation. Mean HbA1c level found to be higher in anemic compared to non-anemic (4.5 vs. 3.96%) in nondiabetic women. Similar to that in women with GDM, mean HbA1c in anemic women (5.1) was higher compared to non-anemic (4.6) women.

This study clearly shows that mean HbA1c varies across all trimesters; even though in diabetic women, mean HbA1c was higher as compared to nondiabetic, and it showed a statistically significant difference in the presence of anemia. HbA1c showed an inverse correlation with hemoglobin in women with or without GDM. Mean HbA1c level was higher among anemic women in both diabetic and nondiabetic group.