Background:Gestational diabetes mellitus (GDM) affects nearly 5% of pregnancies. Significant proportion of the women with previous GDM develops type 2 diabetes mellitus (T2DM) in the next years, which indicates a higher risk in them than in the general population.Objectives:We conducted this study to determine the risk factors and incidence of abnormal glucose level and metabolic syndrome (MetS) in women with a history of GDM in a long period after delivery in our region.Patients and Methods:We extracted the demographic characteristics of 110 women with GDM who had delivered during 2004 - 2010 in three main hospitals of Zanjan City, Iran. The patients were recalled to perform oral glucose tolerance test (OGTT) and other necessary tests for MetS diagnosis. Anthropometric measurements were recorded of all the participants.Results:In this study, 110 women with a history of GDM were studied at one to six years since delivery. Among these women, 36 (32.7%) developed T2DM and 11 (10%) had impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). Moreover, 22 women (20%) had developed MetS. among those with abnormal results in glycemic test, 93.6% had fasting blood sugar (FBS) ≥ 95 mg/dL (≥ 5.27 mmol/L)at the time of GDM diagnosis in the index pregnancy that was significantly higher than the normal glycemic test (NGT) group with 42.9% being affected (OR, 19.55; P < 0.0001). There was a significant difference between those with abnormal results and NGT group in interval between delivery and performing laboratory tests (27 ± 18.8 and 18.5 ± 17.7 months, respectively; OR, 1.02; P = 0.02). No insulin use during pregnancy was discovered as a protective factor in women with a history of GDM (OR, 0.35; P = 0.01). Those with abnormal results were significantly different from NGT group in the number of parities (2.61 ± 1.4 vs. 2.05 ± 1.1, respectively; OR, 1.4; P = 0.03). The most common component of MetS among women with a history of GDM was FBS > 100 mg/dL (> 5.55 mmol/L).Conclusions:Regarding the high incidence of the T2DM and MetS among women with a history of GDM, they should be screened at a regular interval for diabetes and other cardiovascular risk factors.