There are several definitions of postpartum hemorrhage (PPH), with some sensitive and others more specific. Kerr and Weeks reviewed many of the criteria that have been published. The authors are from the University of Liverpool.
Parameters:
(1) blood loss volume in mL
(2) physiologic response
(3) therapeutic response
Criteria for a major PPH might include one or more of the following:
(1) blood loss >= 1,000 mL
(2) shock (with oliguria) secondary to blood loss
(3) transfusion of multiple red blood cell units (>= 5, although a lower cut-off might be used)
(4) emergency hysterectomy
Blood loss from 500 to 1,000 mL without hypotension or intervention can be designated as minor PPH.
Presumably blood loss less than 500 mL would not be viewed as postpartum hemorrhage.
where:
• The volume of blood loss may be difficult to quantitate.
• 500 mL is approximately the volume of a unit of whole blood (not packed RBCs).
• A blood loss of 500 mL may drop hemoglobin 1 g/dL. If a transfusion threshhold of 7 g/dL is used and the woman has a hemoglobin of 13 then blood loss is around 3,000 mL or 6 units of whole blood.
