Chapter 23 Disorders in the puerperium
POSTPARTUM HAEMORRHAGE
Primary postpartum haemorrhage is a blood loss per vaginam of more than 500 mL in the first 24 hours after birth. Secondary postpartum haemorrhage is defined as abnormal bleeding from 24 hours after birth until 6 weeks postpartum.
Primary postpartum haemorrhage (PPH)
Recently many centres are reporting an increase in the rates of postpartum haemorrhage. The reasons for this are not resolved but factors such as increased operative deliveries, multiple pregnancies, obesity and changes in obstetric practice including longer duration of labour and delays in administering prophylactic oxytocics have been postulated as possible contributors.
Aetiology
In normal labour, following the birth of the baby a blood loss of 200–600 mL occurs before myometrial retraction, supplemented by strong uterine contractions. This causes shortening and kinking of the uterine blood vessels and a retraction of the placental bed. These changes prevent further blood loss (Fig. 23.1). Some discussion arises as to whether this traditional quantity of blood loss is an underestimate, when blood loss is measured accurately. Provided the blood loss is less than 800 mL, the woman should have no problems.

Fig. 23.1 ‘Living tourniquet’ of contracted uterine muscle. (A) Uterine muscle fibres relaxed. (B) Contraction of muscle fibres restricts blood flow through the uterine vessels.
If the uterus does not contract effectively (atonic uterus) or if placental remnants prevent good placental site retraction, haemorrhage may occur (‘an empty contracted uterus does not bleed!’). These two causes account for 80% of cases of PPH.
In 20% of cases the cause of bleeding is a laceration of the genital tract, usually of the vagina or cervix, but rarely following uterine rupture (see p. 180). In a few instances PPH follows a blood coagulation defect, such as may occur following abruptio placentae.
Diagnosis
The diagnosis is usually obvious, excessive blood loss occurring before the placenta has been delivered (third-stage bleeding) or following its expulsion. After delivery of the placenta, blood may clot inside the uterus and not be expelled, causing the fundus to rise in the abdomen; if a contraction is rubbed up, the uterus contracts and the clots are expelled. The bleeding tends to be intermittent, as the uterus contracts periodically.
Management
PPH must be dealt with expeditiously, as it is a cause of maternal death. The management differs depending on whether the placenta is still in the uterus or if it has been expelled.
Third-stage bleeding (placenta in the uterus)
True postpartum haemorrhage (placenta expelled)

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