This chapter deals with how to reduce, before delivery, postpartum hemorrhage. The strategy is explained for two risk levels, high and low. Means of prevention such as: logistical organisation; oral and parenteral iron therapy; erythropoietin; autologous blood transfusion; acute hemodilution; transfusion; bleeding disorders treatment; hospitalization, tocolysis, choice of mode of delivery, caesarean section and anaesthetic techniques for placenta praevia or accreta; interest of corticosteroids therapy and magnesium sulfate bleeding risks in severe pre-eclampsia, are addressed in turn. The chapter closes with professional recommendations ranked according levels of evidence founded in the literature.