RESUMO
AIMS: Women diagnosed with Gestational Diabetes Mellitus (GDM) should be evaluated postpartum with an Oral Glucose Tolerance Test (OGTT). Nevertheless, women frequently fail to it. We intend to evaluate the performance of third trimester HbA1c in the prediction of postpartum diabetes mellitus (PDM). METHODS: We conducted a retrospective study of 10245 women with GDM based on the National Registry of GDM. A receiver-operating characteristic (ROC) curve was plotted to evaluate the diagnostic performance of third trimester HbA1c in PDM prediction. RESULTS: The mean third trimester HbA1c level was 5.81% (SD 0.69%) in women who developed PDM, 5.40% (SD 0.52%) in women with pre-diabetes and 5.21% (SD 0.43%) in women with normal glucose tolerance in postpartum OGTT, with statistically significant differences (p < 0.0001). As to the ROC curve ability to predict PDM was fair, with an optimal cut-off point of HbA1c of 5.4%. Women presenting HbA1c values ≥ 5.4% were 6.1 times more likely to develop PDM. CONCLUSIONS: A third trimester HbA1c level ≥5.4% is associated with a significant higher risk of PDM (p < 0.0001). It could be used as a reliable tool for screening women with GDM and detect who will benefit the most from a close follow-up after pregnancy.
