The term postpartum hemorrhage (PPH), in its wider meaning, includes all bleeding after the birth of a baby—before, during, and after the delivery of the placenta. By definition, loss of more than 500 mL of blood during the first 24 hours constitutes PPH. After 24 hours, it is called late PPH. The incidence of PPH worldwide is about 5 percent and is a major contributor to maternal mortality.
During normal delivery, an average of 200 mL of blood is lost. Episiotomy raises this figure by 100 mL and sometimes more. Pregnant women have an increased blood volume, enabling the healthy patient to lose 500 mL without serious effect. To a patient with anemia, however, an even smaller amount of bleeding can be dangerous.
The clinical picture is one of continuing bleeding and gradual deterioration. The pulse becomes rapid and weak; the blood pressure falls; the patient turns pale and cold; there is shortness of breath, air hunger, sweating, and finally coma and death. A treacherous feature of the situation is that because of compensatory vascular mechanisms, the pulse and blood pressure may show only moderate changes for some time. Then suddenly the compensatory function can no longer be maintained, the pulse rises quickly, the blood pressure drops suddenly, and the patient is in hypovolemic shock. The uterine cavity can fill up with a considerable amount of blood, which is lost to the patient even though the external hemorrhage may not be immediately apparent or visibly alarming.
Danger of Postpartum Hemorrhage
The danger of PPH is twofold. First, the resultant anemia weakens the patient, lowers her resistance, and predisposes to puerperal infection. Second, if the loss of blood is not arrested, death will be the final result.
Studies of Maternal Deaths
Studies of maternal deaths show that women have died from continuous bleeding of amounts that at the time were not alarming. It is not the sudden gush that kills, but the steady trickle. In a large series of cases, Beacham found that the average interval between delivery and death was 5 hours, 20 minutes. No woman died within 1 hour, 30 minutes of giving birth. This suggests that there is adequate time for effective therapy if the patient has been observed carefully, the diagnosis made early, and proper treatment instituted.
The causes of PPH fall into four main groups:
The control of postpartum bleeding is by contraction and retraction of the myometrial fibers. This causes kinking of the blood vessels, cutting off flow to the placental site. Failure of this mechanism, resulting from disordered myometrial function, is called uterine atony and is the main cause of ...