Gestational diabetes mellitus (GDM) is a common pregnancy complication, characterized by insulin resistance and low-grade systemic inflammation with a pro-inflammatory immune system response. Our objective was to study the peripheral Th1, Th2, Th17 and Treg response in GDM compared to normal pregnancy. Th1, Th2, Th17 and Treg subsets was determined by flow cytometry based on staining for specific intracellular cytokines, as well as C-reactive protein (CRP) and total IgE circulating levels. The health status of all offspring was also assessed 6 months post-delivery. A total of 49 Caucasian adult pregnant women were enrolled into a GDM (n=26) and Control (n=23) group. At the third trimester of pregnancy, the GDM group had a higher proportion of Th2, Th17 and Treg cells compared to control. Contrary to the control group, the GDM group exhibited no significant change in the Th1/Th2/Th17/Treg profile postpartum. Furthermore, higher circulating CRP and total IgE levels were noted in the GDM group compared to controls. At the 6-month post-delivery assessment, 30.8% of the offspring from the GDM group were found to have developed atopic dermatitis, food allergy or allergic proctocolitis compared to none from the control group. Compared to an uncomplicated pregnancy, GDM exhibits a significantly different peripheral T-cell profile at the third pregnancy trimester characterized by higher proportion of Th2, Th17 and Treg cells which persist six months post-delivery, while the increased high sensitivity CRP (hsCRP) levels stressed the low-grade inflammatory profile of this disease.