Résumé : BACKGROUND: The aim of this study was to investigate whether a higher incidence of hyperinsulinism is found in women who have suffered from ovarian hyperstimulation syndrome (OHSS) as compared with other IVF patients. Additionally, we also assessed whether any abnormalities in the haemostatic system were more frequent in women with a past history of OHSS. METHODS: A pilot study was carried out involving OHSS patients and matched IVF patients. Homeostasis model assessment (HOMA) of insulin sensitivity was calculated. The main outcome measures were: insulin sensitivity, coagulation anomalies, factor V Leiden mutations, methylene tetrahydrofolate reductase (MTHFR) polymorphism and prothrombin gene mutation, protein C and protein S deficiency. RESULTS: No increased incidence in hyperinsulism nor in abnormalities of the haemostatic system were observed. CONCLUSIONS: This pilot study does not provide evidence for an increased prevalence of hyperinsulinism among women who have developed OHSS in the past.