How is postpartum hemorrhage (PPH) defined?

Updated: Jun 27, 2018
  • Author: John R Smith, MD, FACOG, FRCSC; Chief Editor: Ronald M Ramus, MD  more...
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The definition of PPH is somewhat arbitrary and problematic. PPH is defined as blood loss of more than 500 mL following vaginal delivery or more than 1000 mL following cesarean delivery. [5, 6] A loss of these amounts within 24 hours of delivery is termed early or primary PPH, whereas such losses are termed late or secondary PPH if they occur 24 hours after delivery. This article focuses on early PPH.

Estimates of blood loss at delivery are subjective and generally inaccurate. Studies have suggested that caregivers consistently underestimate actual blood loss. Another proposal suggests using a 10% fall in hematocrit value to define PPH, but this change is dependent on the timing of the test and the amount of fluid resuscitation given. [7] More importantly, the diagnosis would be retrospective, perhaps useful for research but not so in the clinical setting.

Another consideration is the differing capacities of individual patients to cope with blood loss. A healthy woman has a 30-50% increase in blood volume in a normal singleton pregnancy and is much more tolerant of blood loss than a woman who has preexisting anemia, an underlying cardiac condition, or a volume-contracted condition secondary to dehydration or preeclampsia. For these reasons, various authors have suggested that PPH should be diagnosed with any amount of blood loss that threatens the hemodynamic stability of the woman.

The diagnosis of PPH is usually reserved for pregnancies that have progressed beyond 20 weeks’ gestation. Deliveries at less than 20 weeks’ gestational age are spontaneous abortions. Bleeding related to spontaneous abortion may have etiologies and management in common with those for PPH.

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