Abstract: Although any pregnant woman can be considered at risk for peripartum bleeding, the degree of risk is suggested by various medical and obstetrical factors. Preexisting coagulation disorders caused by hematological or systemic diseases, the therapeutic use of anticoagulants, anemia and nutritional deficiencies are some of the predisposing
medical factors to which obstetrical factors such as uterine atony, abnormal placentation, obstetrical trauma and peripartum coagulopathy can be added. A number of high-risk entities, the most complex of which is coagulopathy, stand out among the numerous factors which contribute to the ever-present risk of peripartum hemorrhage. Obstetrical complications are patho-physiologically enmeshed with the adaptive changes which take place during pregnancy. Coagulopathies act either as a morphological substrate or a complication of obstetrical emergencies such as small and frequent, or, conversely, abundant hemorrhages, obstetrical shock from prolonged labor,
retention of a dead fetus, important third-trimester dysgravidia, placental abruption or amniotic fluid embolism. Hemostasis differ between pregnant and non-pregnant women. The adaptative changes in hemostasis during
pregnancy are mainly attributed to the higher level of estrogens and affect a number of concurrent elements: vascular capacity, platelet function, serum levels of the coagulation factors and fibrinolysis. Although changes in plasma factors, thrombocytopenia and alterations in blood flow do not alter hemostasis during pregnancy, labor or the puerperium, they may reveal the presence and/or aggravation of certain illnesses which are associated
with or induced by pregnancy. Protective endothelial mechanisms and molecules such as antioxidants, natural antiaggregants and the balance between prostacyclin and endoxane have been described in normal pregnant
women. The main causes of postpartum hemorrhage are uterine atony, abnormal placentation, obstetrical trauma, acquired coagulopathies and illnesses associated with and specific to pregnancy which are accompanied
by coagulation disorders. In the present review, further inside in the coagulation disorders which accompany amniotic fluid embolism, dead fetus retention, sepsis, maternal hypertension, premature detachment of a normally inserted placenta and obstetrical trauma is presented. Moreover, bacterial endo- and exo-toxins and the antibodyantigen complexes produced in sepsis act as a trigger for disseminated intravascular coagulation is described.
DOI:10.18643/gieu.2013.19