Determinar if pregestational obesity is a factor associated with early postpartum haemorrhage at Regional Hospital of Trujillo. MATERIAL AND METHODS: An analytical retrospective cohort study was carried out with a study population that was extracted from medical records of first time pregnant women whose delivery was treated at the Regional Hospital of Trujillo, after applying criteria of inclusion and exclusion the final sample consisted of 195 patients these were divided into two groups 65 to the exposed cohort (with pregestational obesity) and 130 for the unexposed (no pregestational obesity). RESULTS: Of the exposed population 14% of pregnant women presented early postpartum haemorrhage compared to 5% of the unexposed population. The relative risk of pregestational obesity in relation to early postpartum haemorrhage was 3 (95% CI: 1.116-8.067). CONCLUSIONS: Pregestational obesity if ...