Causes And Risk Factors Of Post Partum Haemorrhage Biology Essay

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Post-partum haemorrhage (PPH) refers to an estimated blood loss in excess of 500 ml following a vaginal birth and a loss greater than 1000 ml during a Caesarean section. Major haemorrhage is defined as an estimated blood loss of more than 2500 ml or the transfusion of 5 or more units of blood or treatment of coagulopathy.

These values are arbitrary as visual estimation of blood loss is not reliable. Patients with a low body mass index have a lower blood volume of 70 ml/kg and anaemic women have fewer reserves to withstand blood loss and hence will decompensate sooner. Thus, a useful definition takes into account any blood loss that causes a major physiological change like a fall in blood pressure, as the risk of dying from PPH depends on the amount and rate of blood loss and the woman's health.

PPH is classified as primary and secondary. Primary PPH occurs within 24 hours of delivery and secondary PPH after 24 hours and within 6-12 weeks post-partum.

Causes and risk factors

PPH is commonly due to one or a combination of four processes referred to in the '4Ts' mnemonic:

• tone (post-delivery poor uterine contraction)

• tissue (blood clots and/or retained products of conception)

• trauma (genital tract)

• thrombin (coagulation abnormalities).

Common risk factors for PPH are an over-distended uterus due to fetal macrosomia, multiple pregnancy and polyhydramnios. Antepartum haemorrhage, chorio-amnionitis, coagulation disorders, fibroid uterus, induction of labour, instrumental delivery, obesity, pre-eclampsia, previous Caesarean section delivery, previous history of PPH, primigravidity, prolonged rupture of membranes and/or labour are also considered to be risk factors.

There is a trend in the UK towards delaying child-bearing. Increased maternal age, Caesarean and instrumental deliveries and placenta praevia increase the incidence of PPH. An increasing number of multiple pregnancies due to assisted reproduction can also result in an increased incidence of PPH.

PPH can occur in women without identifiable risk factors. In absolute numbers, more women without risk factors have atonic PPH as compared with those with risk factors.


The blood vessels supplying the placental bed pass through an interlacing network of muscle fibres of the myometrium. Myometrial contraction causes placental separation and causes blood vessels to constrict. This haemostatic mechanism or 'living ligatures' control the bleeding from the placental bed when the placenta separates. Uterine atony results in a failure of these 'living ligatures' to stop the bleeding. The active management of the third stage of labour is associated with a reduction in the risk of PPH and less need for blood transfusion by enhancing the above physiological process.

Mild shock occurs when 20% of the blood volume is lost, resulting in decreased perfusion of non-vital organs and tissues (i.e. bone, fat, skeletal muscle) with pale and cool skin. When 20-40% of the blood volume is lost, moderate shock occurs with decreased perfusion of vital organs (i.e. gut, kidneys, liver), oliguria and/or anuria, a drop in blood pressure, and mottling of the skin in the legs. When 40% or more of the blood volume is lost, severe shock occurs resulting in decreased perfusion of the heart and brain, agitation, restlessness, coma, echocardiogram and electroencephalogram abnormalities, and finally cardiac arrest.

Prevention of PPH

Only 40% of women who develop PPH have an identifiable risk factor. Women with risk factors should be delivered in centres with transfusion and intensive care unit facilities. The Royal College of Obstetricians and Gynaecologists (RCOG) urges early or prophylactic interventional radiology for the prevention and management of PPH in high-risk cases and recommends strategies for the management of unpredicted PPH.

Prevention of PPH includes antenatal risk assessment and treatment of anaemia or other health problems so that women are healthy enough to withstand PPH, as well as appropriate intra-partum and post-partum management. The International Confederation of Midwives and the International Federation of Gynecology and Obstetrics (FIGO) have together launched a world-wide programme to promote active management of the third stage of labour for all women. Active management consists of interventions designed to facilitate placental delivery by improving uterine contractions and preventing PPH by averting uterine atony. These measures include administration of uterotonic agents, controlled cord traction and uterine massage after delivery of the placenta, as deemed appropriate. This approach reduces the risks of PPH, anaemia, requirement for blood transfusion, prolonged third stage of labour and use of therapeutic drugs for PPH. It is recommended that active management should be routine for women in maternity hospitals and there is no evidence to suggest that this recommendation should not include low-risk births at home or in birth centres.

Oxytocin is used routinely in the active management of the third stage of labour. It is routinely administered for the prevention and treatment of PPH as a first-line agent as it is effective within 2-3 minutes after injection and, as it has minimal side effects, it can be used in all women. If oxytocin is unavailable, ergometrine maleate 0.5 mg intramuscularly, ergometrine with oxytocin 5 IU/ml (syntometrine) or misoprostol 0.4 mg orally can be used.

Misoprostol - which is a prostaglandin E1 analogue - can be administered by oral, sublingual and rectal routes. The main side effects are diarrhoea, nausea and vomiting. Rectal misoprostol causes less shivering and pyrexia, than oral misoprostol. A recent Cochrane review on the use of prostaglandins for the prevention of PPH concluded that neither intramuscular prostaglandins nor misoprostol are preferred to conventional injectable uterotonics as part of the management of the third stage of labour especially for low-risk women.

Carbetocin is a long-acting oxytocin agonist and has been used for the prevention of PPH. The advantage of intramuscular carbetocin over intramuscular oxytocin is its longer duration of action. It induces a prolonged uterine response post-partum, both in amplitude and frequency of contraction. Carbetocin is associated with reduced need for other uterotonic agents and uterine massage, and there are no differences in side effects between carbetocin and oxytocin.

FIGO recommends that skilled birth attendants should use physiological (or expectant) management of the third stage if oxytocin or misoprostol are unavailable.

In 2006, the World Health Organization held a technical consultation on the prevention of post-partum haemorrhage and it recommends the following.

• Active management of the third stage of labour should include: administration of an uterotonic soon after the birth of the baby; delayed cord clamping; and delivery of the placenta by controlled cord traction followed by uterine massage.

• Active management of the third stage of labour should be offered by skilled attendants, as potential risks such as uterine inversion, may result from inappropriate cord traction.

• Oxytocin should be offered for the prevention of PPH in preference to oral, sublingual or rectal misoprostol.

• In the absence of active management of the third stage of labour, an uterotonic drug (oxytocin or misoprostol) should be offered.


A management algorithm - HAEMOSTASIS - has been proposed to aid stepwise management of atonic PPH. The following section has been adapted from: Chandraharan E & Arulkumaran S. Management algorithm for atonic postpartum haemorrhage. J Psychosom Obstet Gynaecol June 2005: 106-112 and Doumouchtsis SK, & Arulkumaran S. Postpartum haemorrhage: changing practices. In: Recent Advances in Obstetrics and Gynaecology. Vol 24. Dunlop W, Ledger WL (eds). London: The Royal Society of Medicine Press Ltd; 2008. pp. 89-104.


General medical management


Call for help


Assess (vital signs, blood loss) and resuscitate


Establish aetiology, ecbolics, ensure availability of blood

Establish aetiology: '4Ts' - tone, tissue, trauma, thrombin

Ecbolics (syntometrine, ergometrine, bolus syntocinon)

Ensure availability of blood and blood products


Massage the uterus


Oxytocin infusion, prostaglandins (intravenous, rectal, intramuscular, intramyometrial)

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Specific surgical management


Shift to operating theatre - bimanual compression anti-shock garment, especially if transfer is required


Tissue and trauma to be excluded and proceed to tamponade with balloon or uterine packing


Apply compression sutures


Systematic pelvic devascularisation (uterine, ovarian, quadruple, internal iliac)


Interventional radiology, uterine artery embolisation


Subtotal or total abdominal hysterectomy

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H - Call for help

Major PPH must be managed appropriately by a multidisciplinary team. Consultant obstetricians, anaesthetists, haematologists, midwives, theatre staff, blood bank, hospital porters and even the intensive care/high dependency unit staff should be alerted.

A - Assess (vital signs, blood loss) and resuscitate

Early recognition, prompt resuscitation and restoration of the circulating blood volume are the components in the management of PPH. General resuscitation measures include assessment of the haemodynamic status by monitoring the patient's vital parameters (level of consciousness, blood pressure, pulse and oxygen saturation).

Accurate estimation of the blood loss warns of impending haemorrhagic shock. Different methods of estimation have been evaluated and guidelines to improve accuracy of the visual estimation of blood loss have been suggested. Two large bore cannulae are inserted and blood samples taken for full blood count, group and save and cross-match, coagulation screen and renal and liver profile.

Fluid resuscitation in PPH is often conservative because of underestimation of blood volume and rapid blood loss. It is important to remember that symptoms of hypovolaemia are often delayed due to compensatory mechanisms as these women are fit and young. Concerns that fluid overload will lead to pulmonary oedema and cardiac failure, may be misleading. A loss of 1 litre of blood requires replacement with 4-5 litres of crystalloid (0.9% normal saline or lactated Ringer's solution) or colloids until cross-matched blood is made available, as most of the intravenous fluid shifts from the intravascular to the interstitial space.

'The golden first hour'

Severe haemorrhage leads to cardiovascular failure if not diagnosed and treated effectively. As the severity depends on body weight and metabolism and haemoglobin levels, emergency measures should be initiated if the estimated blood loss is more than one-third of the woman's blood volume (blood volume [ml] = weight [kg] Ã- 80) or more than 1000 ml or a change in haemodynamic status.

As more time passes between the onset of severe shock and effective resuscitation, the chances of survival decrease because metabolic acidosis sets in. The 'golden first hour' is the time at which resuscitation must be commenced to ensure the best chance of survival. The probability of survival decreases sharply after the first hour if the patient is not effectively resuscitated.

For the general acute management of PPH a 'rule of 30' has been proposed. If the patient's systolic blood pressure (SBP) falls by 30 mmHg, heart rate (HR) rises by 30 beats/min, respiratory rate increases to >30 breaths/min and haemoglobin or haematocrit drop by 30%, and/or her urinary output is <30 ml/hour, then the patient is most likely to have lost at least 30% of her blood volume and is in moderate shock leading to severe shock.

The use of the 'shock index' (SI) is invaluable in the monitoring and management of women with PPH. It refers to HR divided by the SBP. The normal value is 0.5-0.7. With significant haemorrhage, it increases to 0.9-1.1. The change in SI of an individual patient appears to correlate better in identifying early acute blood loss than the HR, SBP or diastolic blood pressure used in isolation.

E - Establish aetiology, ecbolics, ensure availability of blood

• Establish aetiology: 4Ts - tone, tissue, trauma, thrombin

• Ecbolics (syntometrine, ergometrine, bolus syntocinon)

• Ensure availability of blood and blood products

A systematic assessment to identify the cause of bleeding is made using the '4Ts' mnemonic. Thorough assessment of the uterine tone is followed by uterine massage and administration of uterotonic agents if the uterus is atonic. Exploration of the uterine cavity under anaesthesia is essential to exclude or remove retained placental tissue and membranes. If bleeding persists despite a well-contracted uterus, examination under anaesthesia must include looking for cervical tears or tears in the vaginal vault, as these may involve the uterus and/or broad ligament and may be the cause of retroperitoneal haematomas. Pressure and/or packing are useful to achieve haemostasis and to prevent haematoma formation. Suspect a coagulation defect if retained tissue or trauma is excluded and bleeding continues despite a well-contracted uterus.

Uterine atony is the most common cause of PPH. Medical management consists of oxytocin 10 units by slow intravenous injection, ergometrine 0.5 mg by slow intravenous injection, methergine 0.2 mg intramuscularly, oxytocin infusion, 15-methyl PGF2 intramuscularly or intramyometrially, or misoprostol.

If bleeding continues, blood transfusion must be commenced if the estimated blood loss is over 30% of the blood volume or if the patient is haemodynamically unstable despite aggressive resuscitation. Group O, Rhesus-negative blood should be transfused until grouped and cross-matched blood is available.

Coagulopathy may be due to a number of factors: disseminated intravascular coagulation (DIC); depletion of clotting factors within blood clots ('washout phenomenon'); dilution of clotting factors with crystalloid fluid resuscitation; lack of clotting factors in stored blood; hypothermia; and acidosis secondary to hypoxia. Dilutional coagulopathy occurs when about 80% of the original blood volume has been replaced. One litre of fresh frozen plasma should be administered (15 ml/kg) with every 6 units of blood transfused. Platelet concentration should be maintained at more than 50 Ã- 109 per litre or more than 80-100 Ã- 109 per litre if surgical intervention is likely. Cryoprecipitate (which provides a more concentrated form of fibrinogen) and other clotting factors (VIII, XIII, von Willebrand factor) may be required if there is DIC or if the fibrinogen level is less than 10 g/l.

M - Massaging the uterus

Bimanual uterine massage (vaginal hand in the anterior fornix and abdominal hand on the uterine fundus) is a very effective measure and reduces bleeding even if the uterus remains atonic, allowing resuscitation to be effective and, thus, reducing further blood loss.

O - Oxytocin infusion, prostaglandins

Oxytocin, can be given as a slow intravenous bolus (5 units) or as an infusion (40 units in 500 ml of 0.9% normal saline, infused at a rate of 100-125 ml/hour) in order to maintain uterine contraction. There are no absolute contraindications, but an antidiuretic effect with volume overload can develop with high cumulative doses. If the uterus remains atonic after initial oxytocic therapy, syntometrine or ergometrine can be repeated.

Ergometrine is an ergot alkaloid and hypertension and cardiac disease are contraindications due to the possible development of severe hypertension and myocardial ischaemia.

Carboprost is a prostaglandin F2 analogue administered intramuscularly or intramyometrially. It is a second-line agent for uterine atony (0.25 mg repeated every 15-20 minutes to a maximum dose of 2 mg). It is known to be 80-90% effective in decreasing blood loss due to PPH in cases that are refractory to oxytocin and ergometrine. It is contraindicated in asthma as it is bronchoconstrictive and other side effects include diarrhoea, vomiting, fever, headache and flushing.

Misoprostol is a synthetic prostaglandin E1 analogue and has been used in the management of PPH. Placebo-controlled randomised trials compared misoprostol with placebo and showed that misoprostol use was not associated with any significant reduction of maternal mortality, hysterectomy, additional use of uterotonics, blood transfusion, or evacuation of retained products. Misoprostol was associated with a significant increase of maternal pyrexia and shivering. However, an unblinded trial showed better clinical response to rectal misoprostol than a combination of syntometrine and oxytocin. A recent Cochrane review concluded that the addition of misoprostol with oxytocin is superior to the combination of oxytocin and ergometrine alone for the treatment of primary PPH. As the peak serum concentration of oxytocin is much smaller than oral misoprostol, which reaches its serum peak concentration at 20 min, a combination of these two agents can provide a sustained uterotonic effect.

A number of case reports of empirical 'off-label' use of recombinant activated factor VII show that it may be an alternative haemostatic agent when the standard treatment is ineffective.

The Scottish Confidential Audit of Severe Maternal Morbidity recommends that, if conservative measures fail to control haemorrhage, surgical haemostasis should be commenced 'sooner rather than later'. Other reports from the RCOG recommend that obstetricians must consider all available interventions to stop haemorrhage including B-Lynch suture, uterine artery embolisation or even radical surgery.

Recommendations have been made that all hospitals with delivery units should aim to provide an emergency interventional radiology service as these have the potential to save the lives of patients with massive PPH.

The American College of Obstetricians and Gynecologists suggests that uterine tamponade can be effective in decreasing haemorrhage secondary to uterine atony, and procedures such as uterine artery ligation or B-Lynch suture may be used instead of the need for hysterectomy. In patients with stable vital signs but persistent bleeding, arterial embolisation is suitable, especially if the rate of blood loss is not excessive.

S - Shift to operating theatre (anti-shock garment, especially if transfer is required and bimanual compression)

In home births and midwifery-led units, transfer to a centre with greater facilities is indicated at this stage. A new type of non-pneumatic anti-shock garment (NASG) can reverse the effect of shock on the body's blood distribution by applying external counter pressure to the legs and abdomen and returning blood to the vital organs, thus keeping the woman stabilised until she reaches a hospital.

A pilot study showed that in women in whom the NASG was used, compared with women in a control group, bleeding decreased by 50% in those experiencing various forms of obstetric haemorrhage (e.g. post-abortion complications, PPH or ruptured ectopic pregnancy). The use of this device could be critical in reducing maternal mortality in low-risk areas where reaching a health facility could take time.

T - Tissue and trauma to be excluded and proceed to tamponade with balloon or uterine packing

Continuous bleeding indicates transfer to and evaluation in the operating theatre. Examination with appropriate lighting, equipment, analgesia and assistance permits assessment of the uterine tone and excludes retained tissue and trauma. Bimanual uterine compression helps to control bleeding while monitoring and resuscitation continues and preparations are made for further interventions.

Uterine packing has always been considered effective, quick and safe for controlling PPH. The use of uterine packing in the management of PPH fell into disrepute in the 1960s following concerns that it: (i) was potentially traumatic and time-consuming; (ii) might conceal ongoing haemorrhage; (iii) might predispose to the development of infection; and (iv) represented a 'non-physiological approach'. More recently, studies concluded that uterine packing is a safe, quick and effective procedure for controlling PPH.

Successful use of uterine balloon tamponade has been reported using a number of devices, including a Bakri balloon, a condom, a Foley's catheter, the Rusch urological hydrostatic balloon and the Sengstaken-Blakemore oesophageal catheter (SBOC). The SBOC has been the most frequently used and reported device.

Overall, the reported success rates vary between 70% and 100%. Uterine tamponade with the SBOC has been described as a prognostic test in obstetric haemorrhage. The 'tamponade test' has had a positive result of >87% for the successful management of PPH in these studies.

The 'tamponade test' arrests bleeding in most women with severe PPH and allows the obstetrician to identify women requiring a laparotomy. This method has the advantages that: (i) insertion is easy and rapid with minimal anaesthesia; (ii) it can be performed by relatively inexperienced personnel; (iii) removal is painless; and (iv) failed cases can be identified rapidly. The early use of balloon tamponade results in reduced total blood loss and haemorrhage-related maternal mortality. No immediate problems (such as bleeding and sepsis) or long-term complications (such as menstrual and fertility problems) have been reported in women who have undergone uterine tamponade.

A - Applying the compression sutures

If the patient is stable and bimanual compression of the uterus has successfully achieved haemostasis, then compression sutures may be of value. Various modifications have been reported to the original B-Lynch suture technique (Figure 1 and Figure 2). The major advantages are easy application of such sutures and preservation of fertility. The disadvantage is the need for laparotomy. Recognised complications include erosion through the uterine wall, pyometra and uterine necrosis.

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Figure 1. The B-Lynch suture. Reproduced with permission from Sapiens Publishing, 2006.

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Figure 2. Reproduced with permission from Sapiens Publishing, 2006. a Cho's multiple square technique. b Vertical and horizontal compression sutures.

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S - Systematic pelvic devascularisation

Pelvic devascularisation requires laparotomy, and progressive, step-wise devascularisation, whereby the uterine, ovarian and internal iliac arteries are ligated (Figure 3). Internal iliac artery ligation (Figure 4) is effective in arresting bleeding from within the genital tract, however, it takes time, is technically challenging and carries the risk of injury to neighbouring structures.

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Figure 3. Quadruple ligation. Reproduced with permission from Elsevier Publishers, 2008 (Chandraharan E & Arulkumaran S. Surgical aspects of postpartum haemorrhage. Best Practice & Research Clinical Obstetrics and Gynaecology, 2008).

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Figure 4. Internal iliac artery ligation: anatomy of the lateral pelvic wall. Reproduced with permission from Elsevier Publishers (Chandraharan E & Arulkumaran S. Surgical aspects of postpartum haemorrhage, Best Practice & Research Clinical Obstetrics and Gynaecology, 2008).

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Prerequisites include a haemodynamically stable patient, specialist surgical expertise and a patient's desire to preserve her future fertility. The reported success rates are between 40% and 100%. When arterial ligation fails, hysterectomy follows and has a higher morbidity compared with those patients undergoing hysterectomy without previous attempts at arterial ligation.

I - Interventional radiology and uterine artery embolisation

Arterial embolisation under fluoroscopic guidance was first described in 1979. The success rate is as high as 70-100% and the procedure has the potential to preserve fertility. Prophylactic embolisation has a role in an elective Caesarean section when the placenta is thought to be morbidly adherent.

Complications include haematoma formation, infection, contrast-related side effects and ischaemia, resulting in uterine and bladder necrosis. Specialised equipment and an interventional radiologist with a great degree of expertise are prerequisites for this procedure.

A recent systematic review failed to demonstrate that any one method for the conservative management of severe PPH was superior to another. The review recommended that uterine balloon tamponade should be considered as the first step in the management of intractable PPH, which is not due to genital trauma or retained tissue, and which does not respond to medical treatment. The choice of measures employed depends on the available facilities and the degree of ongoing bleeding, the estimated blood loss and the haemodynamic state of the woman.

S - Subtotal or total abdominal hysterectomy

Subtotal or total abdominal hysterectomy is usually a last resort in the management of PPH and must not be delayed if the conservative measures have failed to control it. Subtotal hysterectomy may not be effective when the source of the bleeding is in the lower segment, cervix or vaginal fornices. Hysterectomy is associated with numerous postoperative complications (e.g. bowel injury, fistula formation, pelvic haematoma, sepsis, urinary tract injury, vascular injury). The resultant loss of child-bearing and its psychological consequences must not be underestimated.

All these surgical techniques (uterine tamponade, devascularisation, compression sutures and hysterectomy) require the ready availability of specific instruments and equipment. For this, an obstetric haemorrhage equipment tray on labour ward facilitates prompt surgical management of severe obstetric haemorrhage, and reduces the need for blood transfusion and hysterectomy.


PPH is a major cause of maternal morbidity and mortality. Identification of risk factors antenatally and intra-partum is useful in the prevention and treatment of PPH. Catastrophic and life-threatening haemorrhage is often unpredictable. Prompt resuscitation of the patient with effective restoration of the circulating blood volume and identification of the cause of bleeding should be performed in a multidisciplinary team setting. Rapid and prompt treatment measures should be instituted in a step-wise manner using the algorithm 'HAEMOSTASIS' and assessment tools such as the 'rule of 30' and the 'shock index'. Protocols for the prevention and management of PPH should be constantly updated in every maternity unit. The training of all members of staff in the management of this common obstetric emergency should include regular 'fire drills'.

• Specific management of controlling PPH should go hand in hand with fluid, blood and clotting factor resuscitation

• Every unit should have a protocol to manage PPH in a stepwise manner

• Medical management should precede surgical management

• Simple surgical management (tamponade, brace sutures) is less time-consuming, can be done with minimal training and is effective in more than 80% of cases