Postpartum Haemorrhage

Postpartum haemorrhage (PPH) is a major cause of maternal mortality, worldwide. Average blood loss during delivery increases with the complexity of delivery mode. Traditionally, primary PPH is defined as blood loss of 500 ml or more from the genital tract within the first 24 hours of delivery.11 This has been challenged recently as blood loss measurement is inaccurate. Major obstetric haemorrhage is defined as blood loss of greater than 1000 ml, about 1.3% in the UK.12 Another definition suggests excessive blood loss is marked by a 10% drop in haematocrit or by the need for red cell transfusion. PPH can be divided into primary (within first 24 hours of delivery) and secondary (between 24 hours and 6 weeks post-delivery). Secondary PPH is generally thought to be due to infection.

The aetiology of primary or early PPH is as follows:

• Retained placental fragments.

• Lower genital tract lacerations.

• Uterine rupture.

• Uterine inversion.

• Placenta accreta.

• Hereditary coagulopathy.

Uterine atony complicates one in 20 deliveries, resulting in excessive blood loss when adequate myometrial contraction fails to occur after placental expulsion. Risk factors include conditions where the uterus is overdistended (polyhydramnios, multiple gestation, and foetal macrosomia) or fatigued (rapid or prolonged labour and chorioamnionitis). Antepartum haemorrhage is also a risk factor, but contrary to popular opinion, grand multiparity has not been found to be a risk factor.13

The first step in managing PPH is appreciating its severity and evaluating its primary cause. Appropriate senior help should be sought and each unit should have a PPH protocol that is activated at the time of major obstetric haemorrhage. This should include a dedicated bleep via hospital switchboard, involving all appropriate personnel including obstetricians, anaesthetists, and haematologists (both medical and laboratory staff). Guidelines should be readily available on labour ward and staff education should be undertaken in the form of practice drills. One study showed a significant reduction in the incidence of massive postpartum haemorrhage from 1.7 to 0.45% after dissemination of guidelines and commencement of practice drills.14

There has been some work on the use of the thromboelastograph (TEG) in the assessment and management of major haemorrhage.15

The thromboelastogram is an in vitro monitor of the viscoelas-tic properties of blood. It has never been popular with haematology laboratories as it is not capable of performing multiple batch analysis. TEG detects increasing stickiness as fluid blood becomes clot. The trace monitors the entire process of coagulation and provides information on the rate and the strength of clot formation and its subsequent decay. TEG is capable of making a decision between dilu-tional coagulopathy and DIC. Therefore, it may be a useful tool in deciding management of patients from a blood product point of view.

Uterine atony, the most common aetiology, is diagnosed by bimanual palpation and initially managed by uterine massage and by administration of intravenous oxytocin. When carrying out bimanual uterine compression, the hand in the vagina should elevate the uterus to keep the uterine arteries on stretch. Active management of third stage of labour helps prevent PPH, and routine administration of an oxytocic reduces the risk of PPH by 40%.16 Syntocinon is a synthetic nonapeptide that is routinely administered as a first line agent. It is given as an I.V. bolus (10 iu) or an infusion of 40 units at a rate titrated to control the uterine atony. Ergometrine, an ergot alkaloid can also be used, but not in patients with hypertension as there is a great risk of severe hypertension and myocardial ischaemia.

Prostaglandins are important in the treatment of PPH. The next step is usually to give intramuscular Carboprost, which is 15-methyl prostaglandin F2. This is administered in a dose of 250 /g intramuscularly (skeletal or intramyometrial) every 15 minutes, if necessary, up to a maximum of2 mg. Intramyometrial carboprost is faster and more effective17 and although not licensed for use in this way can be used in individual cases under direct consultant supervision in severe atonic PPH. Misoprostol is a synthetic prostaglandin E1 analogue marketed for the prevention of gastric ulcers. Misoprostol has been extensively studied for the purpose of preventing PPH,18,19 and an oral dose of 200 to 400 xg has the equivalent uterotonic effect on the uterus as intramuscular syntometrine.20 Misoprostol in a dose of 1000 xg, given rectally to PPH cases unresponsive to oxytocin and ergometrine, showed control of haemorrhage in three minutes in all 14 cases.21 Detectable misoprostol can be found in the bloodjust two minutes after oral misoprostol administration. Misoprostol is an oral dose and is stable at room temperature. It has a long shelf life, which would be a major advantage in its use in the developing world.

There are recently published articles on the use of recombinant factor VIIa for treatment of massive obstetric haemorrhage. Recombinant factor VIIa is a vitamin K-dependent protein used in the treatment of individuals with Haemophilia A and B inhibitors, acquired inhibitors, and congenital factor VII deficiency.

Specifically, recombinant factor VIIa complexes to tissue factor and, therefore, promotes the activation of factor X to Xa and activation of factor IX to Ixa. It also promotes generation of thrombin. The rate of thrombin formation is enhanced, leading to a full thrombin burst. This is necessary for providing a fully stabilised fibrin plug with a tight fibrin structure, making it resistant to premature lysis.22 There are also platelet-dependent clotting mechanisms mediated by recombinant factor VIIa that do not need the participation of tissue factor.23 The reports are dramatic, with arrest of severe haemorrhage in 10 minutes. Adverse effects occur infrequently (1%) and include thrombosis and myocardial infarction. The main drawbacks are cost, although possibly decrease in ITU stays and less operative intervention may make it cost effective. The half life is also short at two hours and repeated doses may be required.24

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