Answers

Short answers

1 Patients with a large or overdistended uterus (large baby, twins, or hydramnios), trauma (vaginal or uterine tears), or with abnormalities of placental insertion (placental abruption or placenta praevia).

2 Uterine massage or bimanual uterine compression, oxytocin or per rectal misoprostil (or both), recombinant factor VII, intrauterine balloon tamponade, hysterectomy, surgical ligation of the internal iliac arteries, and transcatheter embolisation of the uterine arteries.

3 It is minimally invasive and achieves (reversible) control of proximal and distal bleeding points without necessitating direct surgical visualisation; minor risks include non-target embolisation and self limiting postembolisation syndrome.

4 In patients with known abnormal placentation, balloons can be positioned across the origins of the internal iliac arteries or into the ostia before delivery to reduce blood loss during caesarean section.

Long answers
The World Health Organization’s definition of primary postpartum haemorrhage is the loss of 500 ml or more from the genital tract within 24 hours of giving birth.¹ Worldwide, more than 125 000 women die of postpartum haemorrhage annually.²

1 Risk factors
Although postpartum haemorrhage can occur during any delivery, the risk is increased in certain women. Risk factors (tables 1 and 2) include a large or overdistended uterus (large baby, twins, or hydramnios), trauma (vaginal or uterine tears), and abnormalities of placental insertion (placental abruption or placenta praevia). Appreciation of risk facilitates strategic planning of delivery and support services.³

View this table: [in this window] [in a new window]   Table 1  Risk factors identifiable before the onset of labour3

 

View this table: [in this window] [in a new window]   Table 2  Risk factors identifiable after onset of labour3

 
2 Management
Successful management relies on early diagnosis, resuscitation, and arrest of haemorrhage. Appropriate specialists must be contacted at an early stage to ensure a multidisciplinary approach. A recent Healthcare Commission investigation into maternal deaths at Northwick Park Hospital highlighted the role of interventional radiology in the management of these patients.⁴ The aim should be to preserve life and, if possible, fertility.

Provision of embolisation services mandates liaison between obstetric and interventional radiology teams. Peripheral units without on-site interventional radiology should agree on referral strategies with units that can comprehensively manage these patients.⁵

Transfer of actively bleeding patients from outlying units for embolisation has its risks, but such patients can be rapidly stabilised by placing balloons (occlusion balloons or non-compliant standard angioplasty balloons, if necessary) across the origins of the internal iliac arteries via the femoral arteries. This simple temporising procedure can be performed in an outlying hospital by an interventional radiologist from a neighbouring hospital using, for example, the sort of basic fluoroscopy unit readily available in orthopaedic operating theatres. Once stabilised, the patient can be transferred to the treating unit for definitive embolisation using high quality imaging equipment. Iliac artery balloons can easily be left in place for two to three hours before causing irreversible ischaemic injury of the lower limbs.

The patient’s bladder should be emptied and the placenta and remaining membranes manually removed if needed. Bleeding points along the birth canal should be sutured. Several surgical techniques have been described to control haemorrhage, including intrauterine balloon tamponade,⁶ B-Lynch suture (absorbable compression suture),⁷ uterine artery ligation, internal iliac artery ligation, and hysterectomy. It should be noted, however, that the more invasive surgical options can be technically challenging, threaten fertility, and may fail. Although early recourse to hysterectomy has been advocated in the past,⁸ a recent good practice document from the Royal College of Obstetricians and Gynaecologists noted that hysterectomy could be avoided if endovascular techniques were used.⁵ Embolisation also reduces morbidity and mortality, and it can prevent major blood loss and the need for blood transfusion and intensive care.^{4 9 10 11}

Internal iliac artery ligation can be challenging in the presence of ongoing bleeding and haematoma, and it does not stop bleeding—it simply slows it down. It effectively transforms the pelvic arterial system into a venous system,¹² allowing persistent perfusion of the pelvis via myriad collateral routes, particularly in the peripartum state. Uterine artery ligation is technically easier than internal iliac artery ligation,¹³ but because the uterus receives 90% of its blood supply from the uterine arteries, tying these vessels off does not prevent continuing haemorrhage via collateral routes.

Doppler flow velocities recorded in the uterine arteries after bilateral internal iliac artery ligation are no different from preligation values.¹⁴ More importantly, perhaps, ligation of feeding vessels (uterine and internal iliac artery) will, in most cases, preclude subsequent treatment by embolisation because endovascular access to the uterine circulation has effectively been closed.

Embolisation of the pelvic arterial circulation has been used for more than 30 years. It occludes all bleeding points and allows distal vascular control (beyond surgical reach). Temporary occlusive materials recanalise in seven to 10 days, thus limiting the potential for long term pelvic ischaemia. Both uterine arteries must be embolised because considerable cross circulation occurs within the pelvis. Figures 1-3 show the bilateral uterine artery embolisation carried out in this case.

View larger version (56K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 1 "Flush" pelvic angiogram showing active extravasation of contrast from the left uterine artery stump (arrow)

 

View larger version (40K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 2 Late phase angiogram showing extravasation of contrast from the right uterine artery stump region (closed arrow) and pooling of contrast in the pelvic midline (open arrow)

 

View larger version (147K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 3 (A) Embolisation of the left uterine artery stump with a temporary agent (Gelfoam) and fibred coils (arrow). (B) Embolisation of the right uterine artery stump with Gelfoam (arrow)

 
3 Transcatheter embolisation
The benefits of superselective embolisation are that it is minimally invasive, does not require direct visualisation of the bleeding point (because the bleeding point(s) is often visualised by injection of contrast), and it effects a distal reversible control of the bleeding point(s). Subsequent surgical (arterial) ligation is always possible in those rare circumstances when embolisation alone does not control haemorrhage.

Risks include postembolisation syndrome in women with an intact uterus (a self limiting syndrome comprising uterine cramps and fever, which should be treated expectantly), a small risk of non-target organ embolisation (limited by high quality imaging), complications at the femoral artery puncture site (reduced by use of mechanical closure devices, which are especially useful in patients with disseminated intravascular coagulation as a result of blood loss), a small risk of contrast allergy, contrast nephrotoxicity (unlikely in this generally healthy population), and finally a small radiation dose to the pelvis.^{9 10}

4 Interventional radiology
Interventional radiological techniques may be used electively to prevent postpartum haemorrhage in patients with known abnormal placentation. Techniques include intra-arterial (compliant, atraumatic) balloon inflation in or across the internal iliac arteries, balloon inflation in the uterine arteries, and elective transcatheter embolisation of the anterior divisions of the internal iliac or the uterine arteries. Prophylactic balloon inflation significantly reduces perfusion pressure of the uterine arteries during subsequent labour in at risk patients. After delivery or hysterectomy the balloons are deflated and removed.

If hysterectomy is still needed after prophylactic interventional radiology, blood loss, blood transfusion, and numbers of admissions to intensive care are reduced.⁵

Cite this as: BMJ 2008;337:a2425