Materials and Methods: This case series study was conducted on 130 women with gestational diabetes mellitus (GDM) who had normal blood sugar after the delivery. They took 75 g oral glucose tolerance test (OGTT) before hospital discharge and repeated the test 6-12 weeks later.

Results: Totally, 107 (82.3%) patients out of the total participated women were analyzed. Early OGTT, prediabetes, and diabetes were abnormal in 46 (43.0%), 34 (31.8%), and 12 (11.2%) cases, respectively. In addition, they above-mentioned variables were found to be abnormal in 28 (25.2%) 22 (20.6%), and 6 (5.6%) cases 6-12 weeks later. Further, 6-12 weeks later, the OGTT was abnormal (prediabetes and diabetes) in 5 patients (4.7%) with normal early OGTT. Therefore, there was a significant association between the results of early OGTT and those of 6-12 weeks later (P = 0.00). It implies that early OGTT could detect prediabetes and diabetes (abnormal results) with a sensitivity of 82.14% (95% CI, 63.11-93.94) and specificity of 70.89% (95% CI, 59.58-80.57).

Conclusions: In general, early postpartum screening effectively diagnosed women who were at high risk of diabetes mellitus and needed undergoing OGTT 6 weeks later. Identifying high-risk patients who need to return later facilitates the management of patients and sensitizes patients to refer for further examination.