Primary prevention

Your Organisational Guidance

ebpracticenet urges you to prioritise the following organisational guidance:

Multidisciplinaire richtlijn Postpartumzorg in de eerste lijn (deel 1)Published by: Werkgroep Ontwikkeling Richtlijnen Eerste Lijn (Worel)Last published: 2022Guideline multidisciplinaire des soins postnatals dans la première ligne de soins (partie 1)Published by: Groupe de Travail Développement de recommmandations de première ligneLast published: 2022Multidisciplinaire richtlijn Postpartumzorg in de eerste lijn (deel 2)Published by: Werkgroep Ontwikkeling Richtlijnen Eerste Lijn (Worel)Last published: 2024Guideline multidisciplinaire des soins postnatals dans la première ligne de soins (partie 2)Published by: Groupe de Travail Développement de recommmandations de première ligneLast published: 2024

Be aware that the routine use of uterotonics (preferably oxytocin) as part of active management of the third stage of labour is the single most important intervention to prevent PPH.[1][3][5][36] A Cochrane review found low-quality evidence that prophylactic oxytocin compared with no uterotonic or placebo reduced the risk of blood loss >500 mL (average risk ratio 0.51, 95% CI 0.37 to 0.72) and moderate-quality evidence that it reduced the risk of needing therapeutic uterotonics (average risk ratio 0.54, 95% CI 0.36 to 0.80).[50]

Primary prevention of PPH aims to identify women at high risk prior to delivery. By identifying these high-risk women based on antenatal risk factors and taking proactive measures, the aim is to reduce the incidence and severity of PPH.[21][51]

Ensure a risk assessment is undertaken for every woman antenatally and at the time of admission.[3][52]

  • Use the risk assessment to categorise the woman as low, medium, or high risk for PPH.[21]

  • Modify the risk assessment on an ongoing basis if other risk factors (e.g., chorioamnionitis or prolonged labour) develop during labour or the postpartum period.[4][53]

Risk assessment tools

Use risk assessment tools to ensure early identification of patients at risk of PPH. Examples include:

  • Safe Motherhood Initiative Risk Assessment Checklist[7][8] Safe Motherhood Initiative: Risk assessment table: prenatal & antepartum Opens in new window Safe Motherhood Initiative: Risk assessment table: labor & delivery admission/intrapartum Opens in new window

  • California Maternal Quality Care Collaborative Obstetric Hemorrhage Risk Assessment Guide[54][55]

  • Association of Women's Health, Obstetric and Neonatal Nurses PPH Risk Assessment Table.[56]

Risk assessment tools have been shown to identify 60% to 86% of patients who develop PPH.[3][40][52][57]

  • Be aware that these tools are useful but imperfect. Risk assessment tools will identify approximately 25% of women as being at increased risk of PPH, of whom 60% will require blood transfusion.[52]

  • However, since up to 40% of PPH cases occur in women categorised as low risk, it is vital to ensure ongoing risk assessment and close surveillance in all pregnancies throughout the antepartum, labour, delivery, and postpartum course.[40][52][57]

The following risk factors are included in common risk assessment tools and can assist in triaging patients at highest risk for PPH:[7][8][54][56]

  • Placenta previa/low lying placenta

  • Placenta accreta spectrum (PAS)

  • Platelet count <70 × 10⁹/L (<70,000 per microlitre)

  • Active bleeding

  • Inherited coagulopathy (e.g., von Willebrand disease, haemophilia)

  • Acquired coagulopathy (e.g., amniotic fluid embolism).

Antenatal risk management

During the antenatal period, women identified as high risk for PPH should receive targeted interventions.

  • This may include interventions to increase their iron stores and address underlying anaemia, as adequate iron levels are crucial for maintaining healthy blood volume and preventing excessive bleeding during and after childbirth.[21][44] All pregnant women should be offered screening for anaemia, with oral iron supplementation recommended for any woman with haemoglobin level outside the normal range and parenteral iron therapy considered for any woman who fails to respond to oral iron.[4]

  • The selection of an appropriate delivery location is also essential to ensure timely and effective management of PPH if it occurs.[4][21] For example, women with known risk factors for PPH should be delivered in an obstetric unit in a hospital with an on-site blood bank.[4][53] Additionally, any woman with PAS should be managed in an appropriately resourced setting for delivery.

  • For women identified as having a heightened risk of haemorrhage due to suspected morbidly adherent placenta, a proactive management approach is of utmost importance. Scheduling surgery in advance, preferably in a facility with comprehensive capabilities, facilitates timely involvement of consulting teams and ensures immediate access to the blood bank for any emergent requirements.[51]

  • Women who refuse blood products (including Jehovah’s Witnesses) present a significant opportunity for antenatal prevention planning by a multidisciplinary team. Preparation for treatment of potential haemorrhage with alternative interventions can form part of that plan.[7][52] One study found that Jehovah’s Witnesses were at a 44-fold increased risk of maternal death due to obstetric haemorrhage compared with the general obstetric population.[58]

Risk management on admission and during delivery

Upon admission to the labour and delivery unit:[7]

  • Women identified as high risk for PPH should have a blood sample sent for type and cross-match to ensure the availability of at least 2 units of red blood cells in case they are needed for transfusion during or after delivery.[21]

  • Women deemed to be at medium risk for PPH should have an initial type and screen ordered.

Active management of the third stage of labour is the single most important intervention to prevent PPH and has been shown to decrease the risk of PPH by approximately 66% compared with expectant management.[52][59]

  • The UK National Institute for Health and Care Excellence (NICE) recommends advising women that for every 1000 women who opt for active management of the third stage of labour, there will be 120 fewer PPH cases with bleeding >500 mL and 16 fewer cases with bleeding >1000 mL when compared with physiological management of the third stage.[53]

The three components of active management are administration of prophylactic uterotonics (preferably oxytocin); uterine massage; and umbilical cord traction.[3]

  • The routine use of postpartum oxytocin as a prophylactic uterotonic for all births has been endorsed as one of the most effective methods for the prevention of PPH by multiple organisations, including the World Health Organization (WHO), the American College of Obstetricians and Gynecologists (ACOG), and the International Federation of Gynecology and Obstetrics (FIGO).[1][3][4][5][8][52][59][60]

  • Oxytocin should be administered immediately postpartum following delivery of the anterior shoulder. Intravenous administration is preferred over the intramuscular route by international guidelines in any situation where the woman giving birth already has intravenous access.[61] However, the UK Royal College of Obstetricians and Gynaecologists (RCOG) recommends intramuscular oxytocin as the agent of choice for PPH prophylaxis in the third stage of labour for women without any risk factors for PPH who are delivering vaginally. Intravenous oxytocin is recommended for women delivering by caesarean section.[4] In the UK, NICE has concluded that oxytocin plus ergometrine may be more effective than oxytocin alone in reducing the risk of PPH and the combination is advised for women with risk factors for PPH.[53]

  • By contrast, the evidence is conflicting on whether uterine massage and controlled umbilical cord traction decrease the incidence of PPH.[3][62][63] In particular, the WHO and FIGO recommend against controlled cord traction for vaginal births in settings where skilled birth attendants are unavailable, although cord traction is the recommended method for the removal of the placenta in caesarean section.[1][5] The UK RCOG has stated that uterine massage is of no benefit in prophylaxis of PPH.[4]

In the UK, for women who have had a caesarean birth, NICE recommends offering slow intravenous injection of carbetocin (an oxytocic drug) for prevention of PPH.[53]

Antenatal diagnosis of PAS disorders

PAS disorders, including placenta accreta, increta, and percreta, significantly increase the risk of PPH and are the most common cause of massive bleeds.[26][27][28]

[Figure caption and citation for the preceding image starts]: Placenta percreta invading the uterine myometrium and the serosaChandraharan E, et al. BMJ 2017; 358 :j3875; used with permission [Citation ends].com.bmj.content.model.Caption@1e8173ca

Antenatal diagnosis of PAS disorders with obstetric ultrasound or magnetic resonance imaging (MRI) is extremely useful for surgical planning. In cases of PAS disorders, the UK RCOG recommends planned caesarean delivery at 35-36 weeks' gestation whereas the ACOG recommends this at 34-35 weeks.[64][65]

  • Obstetric ultrasound and MRI have significant diagnostic accuracy in detecting PAS disorders (sensitivity of 94% and specificity of 84%).[66]

  • Obstetric ultrasound is the gold standard investigation for this purpose. The European Working Group on Abnormally Invasive Placenta proposed standardised descriptions of ultrasound signs used for the antenatal diagnosis of PAS. These include loss of the retroplacental clear space, presence of myometrial thinning, placental lacunae, hypervascularity, and presence of a bladder bulge.[67] These ultrasound signs overall have been found to have 91% sensitivity and 97% specificity for the detection of PAS in a systematic review.[68]

  • MRI may be less accessible and more expensive than obstetric ultrasound, with fewer providers skilled in antenatal diagnosis of PAS on MRI. MRI may be complementary to ultrasound and considered in cases where the diagnosis remains unclear on ultrasound in the setting of a posterior or lateral placenta, or for further assessment of the depth of invasion and suspected organ involvement with placenta percreta.[21][69]

Secondary prevention

A prior history of PPH is one of many factors that increase the risk of PPH. Patients with a history of PPH in a prior pregnancy have been found to have a 3-fold increased risk of recurrent PPH in a subsequent pregnancy compared with women with no prior history of PPH. This risk increased with increasing numbers of previously affected pregnancies.[37] History of severe PPH in a prior pregnancy has been associated with up to an 8- to 9-fold increased risk of recurrent PPH in one study.[38]

It is therefore important to ensure timely risk assessment during the antenatal period for any woman who has a history of PPH in a previous pregnancy. For more details on risk assessment, see Primary prevention. The UK National Institute for Health and Care Excellence recommends that any woman with a history of primary PPH requiring additional treatment or blood transfusion should have subsequent births in an obstetric unit.[53]

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