Postpartum haemorrhage

Postpartum haemorrhage lacks a standard defintion and most of the international guidelines disagree on basic elemsnts of its management. Most of the time, people define in in terms of volume, that being 500ml in the 24 hours following delivery.  Standard peripartum management should include some uterotonic, be it oxytocin, ergometrin or misoprostol. Management of PPH starts with these drugs, moves on to add tranexamic acid and massive 1:1:1 transfusion (maybe even Factor VIIa) and continues through to mechanical compression strategies such as balloon tamponade. Ultimately, definitive management techniques can range from angioembolisation and "stepwise uterine devascularisation" by ligation and finally hysterectomy.

Question 17 from the second paper of 2017 was the first time anybody ever got asked about postpartum haemorrhage in the CICM exam. The examiners wanted to know about the advantages and disadvantages of all the various methods of controlling it. The next time this topic emerged was Question 17 from the second paper of 2018, where the focus shifted to causes and management. Fortunately, with at least one past paper SAQ raising awareness of the candidates, the pass rate had improved from 40.8% to 67.2%. The next appearance was as Question 3 from the second paper of 2020, which was basically identical. We were hit with this again in Question 22 from the first paper of 2021. In short, these questions are becoming a fixed feature of the exam.

As far as published sources go, Chapter 24 from Oh's Manual ("General obstetric emergencies") by Winnie TP Wan and Tony Gin has a brief blurb on "severe obstetric haemorrhage" which offers a short introduction to the subject. What's there is probably not enough to answer Question 17 up to the level of a passing grade. Therefore, even the time-poor candidate will need to read widely. The most comprehensive recent review is probably by the WHO (Recommendations for the prevention and treatment of postpartum haemorrhage, 2012). That's over 40 pages for two SAQs, which does not seem to be a favourable marks-per-effort ratio. A shorter article by Mousa et al (2014) list many treatments, but do not go deeply into the advantages and disadvantages, which basically also fails to answer the question. Weeks (2015) wrote a nice review which does discuss the pros and cons, but fails to cover everything.  Unfortunately the author of this summary has had to compile this table of advantages and disadvantages without any one specific reference to recommend to the candidates. 

Definition of postpartum haemorrhage

Traditionally, it is the loss of more than 500ml of blood in the 24 hours following delivery. Pretty much nobody agrees with this traditional WHO definition, because:

• PV blood losses are usually underestimated
• None of the authors can seem to agree on the exact volume cutoff.
• There does not seem to be any scientific reason to limit the time frame to 24 hours
• The blood loss during a caesarian can often exceed this defined volume (some have proposed 1000ml blood loss as the cutoff)

Dahlke et al (2015) looked at four international guidelines and found that they each had a different definition of PPH. The more disturbing variation was in the recommendations for things like balloon tamponade and hysterectomy, where there were no clear guidelines in the guidelines. Each statement made different recommendations on the basis of the same evidence.

Causes of postpartum haemorrhage

The college answer to Question 17 from the second paper of 2018 recommends to classify the possible causes in the "4 T's" tone, trauma, tissue and thrombin, where:

• Tone: uterine atony 
• Trauma: surgery or injury
• Tissue: retained tissue (placenta) and/or membranes  
• Thrombin: any coagulation defect.

That may represent the minimum expected of a hastily scribbled CICM SAQ answer. For those playing at home (eg. doing these SAQs under exam conditions), some hasty scribbles may not match the college model answer, yet still remain accurate. In those cases it would help to have a  broader range of causes.

Thus:

• Uterine atony
  • Prolonged labor
  • Polyhydramnios
  • Multiple gestations
  • Chorioamnionitis
  • Oxytocin augmentation of labor
• Peripartum uterine trauma
  • Instrumental delivery
  • Surgical mishap
  • Laceration during labour (including episiotomy)
  • Uterine rupture
• Postpartum retained products
  • Placenta 
  • Membranes
• Coagulopathy
  • DIC
  • Amniotic fluid embolism
  • Sepsis 
  • Intrauterine foetal demise
  • HELP
  • Massive transfusion
• Placental abnormality
  • Placenta previa
  • Placental abruption

At some stage, the college may ask for a list of risk factors. One such list is provided by Sheiner et al (2005); this specifically refers to early PPH (i.e. within 24 hours of delivery):

• Retained placenta
• Failure to progress, 2nd stage
• Placenta accreta or praevia
• Lacerations
• Instrumental deliveries
• Large neonate for gestational age
• Hypertensive disorders
• Induction of labor
• Oxytocin augmentation

Advantages and disadvantages of Methods used to Control
Postpartum Haemorrhage

Method	Advantages	Disadvantages
Mechanical haemostasis methods
Uterine massage	Non-invasive Requires zero training Could be performed by the gravida herself May assist in clot expulsion Does not appear to have any harmful effects	May not be effective Time-consuming and requires higher nursing workload Lack of evidence regarding effect (WHO recommend against this practice and describe it as a time-wasting exercise)
Bimanual compression	This is where you a fist in the vagina and a hand on the abdominal wall. Effective to establish haemostasis. Buys time for definitive management	Not exactly a long-term solution All available evidence describing this technique is low quality. All society recommendations in support of it are weak recommendations.
Manual aortic compression	Effective to establish haemostasis Buys time for definitive management	Only available intraoperatively Not exactly a long-term solution
Pharmacological means of encouraging uterine contraction
Oxytocin	Synthetic analogue of endogenous hormone Available widely, and cheap Recommended universally in the management of the third stage of labour (Dahlke et al, 2015) Fewer side-effects than ergometrine	Causes hypotension Contraindicated in pre-eclampsia Even though it's recommended as first  line by everyone, there are not randomised controlled trials which support its efficacy.
Ergometrine	Ergot alkaloid which increases uterine tone Widely available As prophylaxis, it is at least as effective as oxytocin	Causes vomiting, nausea, hypertension; more side-effects than oxytocin Contraindicated in preeclampsia May cause coronary vasospasm May promote the retenion of the plancenta
Carboprost	Synthetic prostaglandin analogue of PGF2α  Increases uterine tone	May cause bronchospasm No agreement as to when this should be used (i.e. no agreement as to where this drug belongs in line after the fisrt-line agents)
Misoprostol	Methyl ester synthetic analogue of  prostaglandin E1 High success rate if used with other uterotonic agents Can be administered orally, sublingually, buccally, vaginally or rectally - by unskilled operators, in a resource poor setting	Not as effective as the other uterotonic agents (Tunçalp et al 2012) Generally, only recommended as a co-uterotonic Only indicated if other uterotonic agents are unavailable or are ineffective
Pharmacological measures to promote haemostasis
Tranexamic acid	Systemic antifibrinolytic Inexpensive and requires minimal training to use Can be added if uterotonics have been ineffective in controlling the bleeding Supported by the WOMAN trial (Shakur et al, 2017) No added risk of VTE, contrary to popular belief (Hibbs, 2018)	Decreased seizure threshold
Factor VIIa	Highly effective after a single dose (Alfirevic et al, 2007)	Expensive May not be available Thrombotic adverse event rate was 2.5% in on study
Surgical or radiological methods of haemostasis
Gause pack tamponade	"several yards of wide gauze placed inside the uterine cavity" Acts by mechanical pressure effect as well as the prothrombotic effect of the fabric	May conceal haemorrhage May encourage infection
Balloon tamponade	Provides more reliable tamponade than gauze packs Includes a drainage channel to monitor blood loss Can be inflated and deflated to test for re-bleeding	Inappropriate if there has been significant genital tract laceration Uncomfortable Invasive
Angio-embolisation	Minimally invasive means of devascularising the uterus May be able to localise the precise territory from where blood loss is occuring	Radiation exposure is involved (not great for the breasts) May not be available everywhere
Ligation of the uterine or common iliac artery	"stepwise uterine devascularisation" should terminate blood supply, preventing further bleeding Apparently, this does not have any major adverse effects on fertility (Doumouchtsis et al, 2013)	Controls bleeding only in 50% of cases
Hysterectomy	May be a lifesaving step	High maternal morbidity Fertility will obviously be affected Bleeding may continue in spite of this procedure, because of coagulopathy A more extensive procedure with risk of complications such as ureteric or bladder injury

For extra credit, the trainees were expected to mention the WOMAN trial (Shakur et al, 2017). Bleeding PPH patients were randomised to receive 1g of tranexamic acid (and another 1g if needed). A whopping 20,060 patients were enrolled. The difference in death from haemorrhage was 1.5% vs 1.9%, in favour of tranexamic acid by 0.4% of absolute risk reduction - a difference which only achieved statistical significance because the numbers were massive and because the sample size was increased by 5000 patients mid-study. The number needed to treat are 267. 

Structured management of postpartum haemorrhage

This structure and a lot of the components are borrowed from the RANZCOG statement C-Obs 43.

Resuscitation

• A: either secure the airway if unprotected,  or prepare to do so with appropriate expertise (i.e. get an anaesthetist)
• B: preoxygenate with high flow oxygen
• C: establish IV access and give a fluid bolus; avoid hypothermia and use fluid warmers
• D: reassure patient and ensure analgesia is adequate
• E: correct ionised calcium (essential component of clotting); corrrect acidosis
• F: monitor fluid resuscitation efficacy by observing urine output
• G: fast the patient in preparation for surgery
• H: correct coagulopathy and commence transfusion
  • Activate massive transfusion protocol: the college answer to Question 17 from the second paper of 2018 mentions the National Blood Authority's obstetric guidelines, which are endoresed by CICM. The guidelines recommend:
    • FFP: 15 mL/kg
    • platelets: 1 adult therapeutic dose
    • cryoprecipitate: 3–4 g
  • Fibrinogen is all-important- the same NBA guidelines recommend a fibrinogen level of > 2.0 as a therapeutic  target
  • Tranexamic acid is also known to be beneficial (WOMAN trial -Shakur et al, 2017) - to be given within 3 hours of haemorrhage
• I: antibiotics are not routinely indicated for primary PPH outside of the scenario of septic abortion or endometritis. 

Specific management

• Uterine massage
• Bimanual compression
• Manual aortic compression
• Oxytocin
• Ergometrine
• Carboprost
• Misoprostol
• Gause pack or balloon tamponade
• Angioembolisation
• Brace sutures
• Ligation of the uterine artery
• Hysterectomy