RESUMEN
Major obstetric hemorrhage remains the leading cause of maternal morbidity and mortality worldwide. Even though blood transfusion may be a life-saving procedure, an inappropriate usage of blood products in obstetric emergencies especially in cases of massive bleeding is associated with increased morbidity and risk of death. Thorough knowledge of the etiology, pathophysiology, and optimal therapeutic options of major obstetric hemorrhage may help to avoid lethal outcomes. There are evidence-based data about some risks related with transfusion of blood components: acute or delayed hemolytic, febrile, allergic reactions, transfusion-related acute lung injury, negative immunomodulative effect, transmission of infectious diseases, dissemination of cancer. This is why the indications for allogeneic blood transfusion are restricted, and new safer methods are being discovered to decrease the requirement for it. Red cell alloimmunization may develop in pregnancy; therefore, all pregnant women should pass screening for irregular antibodies. Antierythrocytic irregular antibodies may occur due to previous pregnancies or allogeneic red blood cell transfusions, and it is important for blood cross-matching in the future. Under certain circumstances, such as complicated maternal history, severe coagulation abnormalities, severe anemia, the preparation of cross-matched blood is necessary. There is evidence of very significant variation in the use of blood products (red cells, platelets, fresh frozen plasma, or cryoprecipitate) among clinicians in various medical institutions, and sometimes indications for transfusion are not correctly motivated. The transfusion of each single blood product must be performed only in case of evaluation of expected effect. The need for blood products and for their combination is necessary to estimate for each patient individually in case of obstetric emergencies either. Indications for transfusion of blood components in obstetrics are presented in order to improve the skills of doctors and to optimize therapeutic options in obstetric emergencies.