ABSTRACT: BACKGROUND: Postpartum haemorrhage (PPH) remains a leading cause of maternal mortality worldwide. In Denmark 2 % of parturients receive blood transfusion. During the course of bleeding fibrinogen (coagulation factor I) may be depleted and fall to critically low levels impairing haemostasis and thus worsening the ongoing bleeding. A plasma level of fibrinogen below 2 g/L in the early phase of postpartum haemorrhage is associated with subsequent development of severe haemorrhage. Use of fibrinogen concentrate allows high-dose substitution without the need for blood type cross match. So far no publications of randomised controlled trials involving acutely bleeding patients in the obstetrical setting have been published. This trial aims to investigate if early treatment with fibrinogen concentrate reduces the need for blood transfusion in women suffering severe PPH. METHODS: In this randomised placebo controlled double blind multicenter trial, parturients with primary PPH are eligible following vaginal delivery in case of: Manual removal of placenta (blood loss [greater than or equal to] 500 ml) or manual exploration of the uterus after the birth of placenta (blood loss [greater than or equal to] 1000 ml). Caesarean sections are also eligible in case of perioperative blood loss [greater than or equal to] 1000 ml. The exclusion criteria are known inherited haemostatic deficiencies, prepartum treatment with anti-thrombotics, pre-pregnancy weight