Maternal Collapse in Pregnancy


Published: 15 December 2021

Maternal collapse is a rare, life-threatening event with a wide range of possible causes that may or may not be pregnancy-related.

Defined as an acute event resulting in a reduced or absent consciousness and potential cardiac arrest, maternal collapse can occur at any stage of pregnancy and up to six weeks postnatally (Chu, Johnston & Geoghegan 2019).

With both mother and baby at risk of potentially life-threatening repercussions, prompt recognition and treatment are vital for effective management. In all cases, the wellbeing of the mother should always take priority in acute collapse scenarios, and only once the mother’s condition has been stabilised should action be taken to support the wellbeing of the baby (Brunskill & Ferriman 2018). Fortunately, maternal collapse is rare in Australia (Hingston 2021) and is an emergency that few midwives will see during their careers.

The outcomes for both mother and baby are dependent on swift action and effective resuscitation, yet, as Catling-Paull et al. (2021) point out, the early warning signs of impending maternal collapse are often absent or go unrecognised.

Maternal deaths are usually expressed as a maternal mortality ratio (MMR), which is the number of maternal deaths per 100,000 women giving birth. Whilst recent evidence points to the rate of maternal morbidity increasing year-on-year, Chu, Johnston and Geoghegan (2019) suggest this is more likely to reflect the changing demographics of women and better reporting, rather than a decline in care.

Evaluating the Risk

As Hingston (2021) notes, maternal collapse can occur any time during pregnancy and up to 42 days following delivery, however, not all maternal deaths are preceded by an identifiable collapse, and not all maternal collapses result in death.

Even though it’s not always possible to predict which women will be at the greatest danger of collapse, some of the most common risk factors can be identified and include:

  • Maternal age of 35 years or older
  • Obesity
  • Lower socioeconomic status
  • Pre-existing mental health issues, substance use or domestic violence
  • Medical co-morbidities, especially asthma, autoimmune diseases or inflammatory disorders.

(Hingston 2021)

maternal collapse practitioner evaluating risk

Haemorrhage is a Leading Cause of Collapse

Of all the potential causes of maternal collapse, haemorrhage is thought to be the most common (Maternal Collapse 2020). Postpartum haemorrhage, antepartum haemorrhage from a placenta praevia, placental abruption, uterine rupture, uterine inversion and ectopic pregnancy are all potential causes of catastrophic maternal haemorrhage (Chu, Johnston & Geoghegan 2019).

Other Possible Causes of Maternal Collapse

Hingston (2021) makes the point that although the leading causes of direct maternal death in Australia are thromboembolic disease and obstetric haemorrhage, other less common causes of collapse also need to be considered. These include:

  • Eclampsia, epilepsy and cerebrovascular accident
  • Myocardial infarction, arrhythmias and congenital heart disease
  • Asthma, pulmonary embolism and pulmonary oedema
  • Anaphylaxis
  • Hypoglycaemia, amniotic fluid embolism and septicaemia
  • Complications of anaesthesia or drug toxicity.

(South Australian Perinatal Practice Guideline 2020)

Emergency Management

In addition to standard resuscitation procedures, some additional factors need to be taken into consideration for pregnant women, such as placing the mother in the left lateral position and administering oxygen whilst all vital signs are being recorded. Assessment of fetal wellbeing should also be performed, but only after the mother’s condition has been assessed and, if possible, stabilised (Chu, Johnston & Geoghegan 2019).

As Hingston (2021) suggests, there are many physiological changes that occur in pregnancy that could potentially make resuscitation more difficult. For example:

  • The weight of a large gravid uterus can cause aortocaval compression if the mother is lying flat on her back, resulting in reduced cardiac output.
  • Depending on the gestation, pressure from the uterus can splint the diaphragm. This might mean increased pressure is needed for successful ventilation.
  • Increased breast tissue can reduce chest wall compliance and potentially make ventilation more difficult.
  • Fetal haemoglobin circulating in the fetus and placenta has a higher affinity for oxygen than adult haemoglobin, which allows the fetus to ‘steal’ oxygen from the mother. This means that oxygen delivery to the maternal brain and myocardium is less efficient than in the non-pregnant patient.
  • The increased plasma volume of pregnancy is linked to dilutional anaemia and can result in reduced oxygen-carrying capacity.
  • Changes in respiratory and metabolic function make acidosis more likely to develop, which means that resuscitation needs to be even more efficient than usual.

(Hingston 2021)

Brunskill and Ferriman (2018) suggest the following key steps that should always be performed in cases of maternal collapse:

  • Identify any antenatal risk factors
  • Manage patients with pre-existing disease in a specialist clinic as part of an interprofessional approach
  • Document a management plan for delivery and the postnatal period for high-risk patients
  • Ensure adequate monitoring of high-risk patients
  • Involve senior clinicians early
  • Ensure all staff are trained in resuscitation techniques for pregnant patients.

Hingston (2021) expands on this and emphasises the importance of maintaining left-lateral displacement of the uterus to reduce the degree of aortocaval compression. This should be achieved manually, with one member of the maternity team using a hand to push the uterus to the side while the mother is supine. Ultimately, it may be necessary to consider expediting delivery with an emergency caesarean section to give both mother and baby the best possible chance of survival.

Survival Rates

In cases where maternal collapse proceeds to cardiac arrest, survival rates tend to be poor, with only 42% of mothers recovering. Swift action is critical, with one study finding that there was a median time of just 3 minutes from collapse to operative delivery for those mothers who survived, and a median time of 12 minutes for those who died (Warren 2021). Beckett, Knight and Sharpe (2017), on the other hand, are slightly more optimistic, suggesting that maternal survival rates of 58% could be achieved with prompt resuscitation.


maternal collapse pregnant patient

With such potentially devastating outcomes, women who are in a high-risk category for maternal collapse should be referred to appropriate specialists who can create a specific pregnancy management plan that highlights any ‘red-flag’ symptoms that might require an urgent referral or specialist review (Bhatti & Penna 2012).

As Catling-Paull et al. (2021) note, it’s a sobering topic that requires a constant updating of training packages, as well as relevant in-service education programs and training in optimal teamwork should collapse occur.

Hingston (2021) sums up the situation succinctly by suggesting that, as with everything in obstetrics, one of the biggest challenges with maternal collapse is the unpredictability and the need for constant vigilance, however rare these events might be.



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Anne Watkins View profile
Anne is a freelance lecturer and medical writer at Mind Body Ink. She is a former midwife and nurse teacher with over 25 years’ experience working in the fields of healthcare, stress management and medical hypnosis. Her background includes working as a hospital midwife, Critical Care nurse, lecturer in Neonatal Intensive Care, and as a Clinical Nurse Specialist for a company making life support equipment. Anne has also studied many forms of complementary medicine and has extensive experience in the field of clinical hypnosis. She has a special interest in integrating complementary medicine into conventional healthcare settings and is currently an Associate Tutor, lecturing in Health Coaching and Medical Hypnosis at Exeter University in the UK. As a former Midwife, Anne has a natural passion for writing about fertility, pregnancy, birthing and baby care. Her recent publications include The Health Factor, Coach Yourself To Better Health and Positive Thinking For Kids. You can read more about her work at