AIMS: Gestational diabetes (GDM) presents an increased cardio-metabolic risk and is diagnosed with an oral glucose tolerance test (OGTT). Reactive hypoglycaemia (RH) during the OGTT in pregnancy is associated with adverse outcomes. Although postpartum OGTT after GDM is recommended, the occurrence and implications of RH are unknown. We investigated the prevalence, metabolic implications and longitudinal evolution of RH at 6-8 weeks postpartum in women with a history of GDM. METHODS: Between 2011 and 2021, we consecutively followed 1237 women with previous GDM undergoing an OGTT at 6-8 weeks postpartum. RH was defined as 2-h glucose