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OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Maternal collapse and perimortem birth principles

Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending

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Start maternal resuscitation immediately

An unresponsive pregnant or postpartum woman who is not breathing normally should be treated as being in cardiac arrest unless rapidly established otherwise.

Action: Call the resuscitation and obstetric teams, start chest compressions, obtain a defibrillator and support ventilation. Above twenty weeks relieve aortocaval compression manually and prepare indicated resuscitative hysterotomy early at the arrest site.

Overview

Distinguish collapse from cardiac arrest, deliver effective maternal resuscitation with pregnancy adaptations, and apply current principles for timely resuscitative birth.

Maternal collapse includes a broad spectrum from transient syncope to profound shock and cardiac arrest. The initial assessment must establish responsiveness, breathing and circulation quickly enough to avoid delaying CPR. In an unresponsive woman who is not breathing normally, start the cardiac-arrest response. In a woman with a pulse, use an ABCDE assessment and treat the life-threatening disturbance while obtaining specialist help; arrest-dose medicines are not interchangeable with treatment of shock in a perfusing circulation.

Pregnancy reduces respiratory reserve and the enlarged uterus can impair venous return when the woman lies supine. These changes make effective oxygenation and relief of aortocaval compression especially important. The older expression perimortem caesarean can misleadingly imply a final attempt after resuscitation has failed. Current RCUK guidance uses resuscitative hysterotomy and stresses preparation early, performance as soon as possible when indicated, and completion where the arrest occurred by a skilled team.

Practice

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Obstetrics and gynaecologyOriginal SBA

Timing and place of resuscitative birth

A woman at 30 weeks arrests on a surgical ward. CPR and manual left uterine displacement have begun, and a skilled obstetric team has arrived with equipment. Circulation has not returned. What does RCUK 2025 recommend regarding indicated resuscitative hysterotomy?

Choose one answer, then submit
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Sources and review status5 sources · checked 7 Sept 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.

  • RCUK 2025: cardiac arrest in pregnancy
  • RCUK 2025: adult advanced life support
  • RCOG Green-top 56: maternal collapse assessment
  • RCUK 2025: newborn resuscitation after birth
  • RCUK 2025: adult basic life support and immediate help-seeking

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom

Key points

  • Use standard high-quality adult BLS and ALS, with pregnancy-specific modifications.
  • Keep the woman supine for effective compressions and use manual left uterine displacement above twenty weeks.
  • Give indicated shocks promptly at standard adult energies; pregnancy is not a reason to withhold defibrillation.
  • Investigate the usual four Hs and four Ts alongside pregnancy-specific causes.
  • RCUK 2025 recommends early preparation and resuscitative hysterotomy as soon as possible by a skilled team at the arrest site.
  • Do not transfer a woman in ongoing arrest to theatre simply to perform resuscitative hysterotomy.
  • Emptying the uterus is a maternal resuscitation intervention, not contingent on proving fetal viability.
  • Continue multidisciplinary post-arrest care and investigate the cause after circulation returns.

Aetiology

01

General adult reversible causes

Pregnant women can arrest from the same cardiac, respiratory, metabolic, traumatic and toxicological causes as other adults. The pregnancy context supplements this differential rather than replacing it.

02

Pregnancy-associated emergencies

Haemorrhage, hypertensive disease, maternal infection and peripartum cardiomyopathy require deliberate assessment. Anaesthetic complications and amniotic-fluid embolism are additional possibilities around labour and birth.

Pathophysiology

  1. 1
    Aortocaval compression

    The gravid uterus can compress major abdominal vessels in the supine position, reducing venous return. Manual displacement and indicated uterine emptying address this obstacle while compressions generate circulation.

  2. 2
    Reduced oxygen reserve

    Pregnancy increases oxygen demand and changes respiratory mechanics, so hypoxaemia can develop quickly when ventilation fails. Effective airway opening and ventilation deserve early skilled attention.

  3. 3
    Low-flow organ injury

    During arrest, inadequate circulation compromises maternal organs and placental oxygen delivery. High-quality CPR, rapid defibrillation when indicated and treatment of reversible causes aim to restore perfusion.

Clinical features and red flags

Identify arrest rather than a label

Call for emergency help as soon as unresponsiveness is identified, while assessing whether breathing is normal. Begin CPR for absent or abnormal breathing. If a trained clinician checks a pulse, uncertainty must not prolong assessment. Agonal gasps and seizure-like activity can accompany cardiac arrest.

Recognise the deteriorating woman

Use maternity early-warning observations and clinical concern to escalate new hypoxia, tachycardia, hypotension, altered consciousness or oliguria. Normal pregnancy physiology should not be used to dismiss a marked change or a woman saying she feels seriously unwell.

Seek the immediate context

Ask about gestation or recent birth, bleeding, hypertensive disease, infection symptoms, cardiac history and recent anaesthetic or medication administration. A brief chronological history from witnesses can identify anaphylaxis, high block, toxicity or haemorrhage without delaying resuscitation.

Identify advanced pregnancy quickly

A visibly enlarged uterus or fundus at or above the umbilical region can indicate clinically important aortocaval compression when dates are unavailable. Do not delay displacement or specialist preparation to obtain a scan or an exact gestational age.

Red flags requiring action

  • Unresponsiveness with absent or abnormal breathing requires immediate recognition of cardiac arrest; gasping is not normal breathing.

Investigations

  1. 01
    Defibrillator rhythm assessmentFirst step
    Why
    Identify shockable or non-shockable arrest and guide immediate ALS.
    Interpretation and limitations
    Analyse rhythm with minimal interruption to compressions. Shock VF or pulseless VT promptly; an organised electrical rhythm requires clinical assessment for circulation rather than assuming that a displayed rhythm means a pulse.
  2. 02
    Waveform capnography after advanced airway placement
    Why
    Confirm tracheal placement and support monitoring of resuscitation quality.
    Interpretation and limitations
    A sustained waveform is needed to exclude oesophageal intubation. Trends may support assessment of perfusion and return of circulation, but a low value alone must not determine termination of CPR.
  3. 03
    Point-of-care glucose and blood gas
    Why
    Identify treatable metabolic disturbance and assess physiological severity.
    Interpretation and limitations
    Check glucose promptly when collapse or seizure is unexplained. Blood gas testing can identify major potassium abnormalities, acidosis and hypoperfusion while the team treats the underlying cause.
  4. 04
    Blood count, coagulation, fibrinogen and compatibility samples
    Why
    Assess suspected obstetric bleeding and prepare component support.
    Interpretation and limitations

Differential diagnosis

01

Vasovagal syncope

A brief faint with rapid recovery may be benign, but persistent abnormal observations, pain or bleeding require a broader evaluation. Do not assume all transient loss of consciousness is uncomplicated syncope.

02

Seizure with preserved circulation

Eclampsia, epilepsy and metabolic disorders can cause seizures without arrest. Assess breathing and circulation directly because seizure-like activity can also mark the onset of cardiac arrest.

03

High neuraxial block

Recent spinal or epidural medication followed by progressive weakness, respiratory difficulty and hypotension suggests a high block. Urgent anaesthetic support and ventilation may prevent progression to arrest.

Management

01First responseStart effective BLS and mobilise expertiseFirst stepA pregnant or recently postpartum woman is unresponsive and not breathing normally.+
  1. 1Call the hospital cardiac-arrest team or emergency services and request obstetric, anaesthetic and neonatal support; bring the resuscitation trolley and birth equipment.
  2. 2Start chest compressions at 100–120 per minute, depth 5–6 cm with full recoil, on a firm surface and with minimal interruption.
  3. 3Use thirty compressions to two breaths until an effective advanced airway permits continuous compressions with appropriate ventilation.
  4. 4Apply defibrillator pads, analyse the rhythm and deliver indicated shocks using the standard adult approach; resume compressions immediately afterwards.
  5. 5Above twenty weeks, assign an assistant to maintain manual left uterine displacement while the woman remains supine for effective CPR.
02

Complications

01

Hypoxic neurological injury

The duration and severity of impaired oxygen delivery influence neurological recovery. Prognostication requires specialist multimodal assessment over time rather than an isolated early sign during resuscitation.

02

Haemorrhage and organ failure

The precipitating obstetric cause or emergency surgery may produce significant bleeding, while low flow can injure kidneys, heart and liver. Ongoing critical care addresses both causes and consequences.

03

Newborn compromise and family distress

Maternal arrest threatens fetal oxygen supply and may necessitate very preterm birth. Separate newborn expertise and clear compassionate communication help the family navigate two simultaneous clinical emergencies.

Monitoring and follow-up

  • Rotate compressors and review compression quality, ventilation, displacement and rhythm at appropriate intervals without creating unnecessary pauses.
  • Track medicines, shocks, access, key clinical findings and procedure times through an assigned recorder to support safe decisions and later explanation.
  • After ROSC, monitor consciousness, oxygenation, circulation, temperature, urine output, lactate and evolving organ injury in critical care.
  • Arrange follow-up that includes physical rehabilitation, cardiac or other cause-specific care and assessment of emotional or cognitive consequences for the woman and her family.

Special situations

Maternal benefit drives resuscitative hysterotomy

Removing the gravid uterine load can improve venous return and the effectiveness of maternal resuscitation. Fetal survival is also desirable, but a viability assessment must not delay a procedure indicated for maternal rescue.

An old timing mnemonic is not a reason to wait

The 2025 RCUK wording prioritises early preparation and performance as soon as possible. Teach the team to mobilise immediately rather than to watch a clock until four minutes before beginning the discussion.

The location matters

Transport during arrest can interrupt compressions and consume time. A skilled team should perform the indicated procedure where the woman arrested, whether that is a ward, emergency department or another hospital area.

ALS is adapted to the cause

Pregnancy does not routinely change shock energy or standard arrest drug doses. A special cause, such as local anaesthetic toxicity, can change the drug strategy and should trigger the relevant resuscitation guidance.

Common pitfalls

  1. 01

    Using lateral tilt that makes compressions ineffective loses the benefit of perfusion support; manual uterine displacement is preferred during arrest.

  2. 02

    Waiting for a fetal heart-rate assessment before preparing resuscitative birth reverses the priority of maternal rescue.

  3. 03

    Applying the cardiac-arrest adrenaline bolus to anaphylaxis in a woman with a pulse is a serious route-and-dose error.

  4. 04

    Assuming every postpartum collapse is obstetric overlooks cardiac disease, pulmonary embolism and other general medical emergencies.

Severe breathlessness, chest pain, seizure, major bleeding or rapidly worsening circulation can precede arrest.
  • A pregnant woman can arrest outside maternity services; the emergency response must bring appropriate skills and equipment to her.
    • Send samples during resuscitation without postponing emergency-release transfusion when indicated. Concealed loss remains possible after caesarean or with uterine, placental or intra-abdominal pathology.
  • 05
    Skilled point-of-care ultrasound and subsequent definitive imaging
    Why
    Identify reversible causes without disrupting life-saving interventions.
    Interpretation and limitations
    Ultrasound may identify tamponade or support assessment of cardiac function, but must not prolong compression pauses. After stabilisation, choose definitive imaging according to the suspected cause rather than avoiding necessary investigations solely because of pregnancy.
    • Parallel ALSTreat rhythm and reversible causesThe resuscitation team has begun CPR and established monitoring.
    +
    1. 1Provide oxygenation and skilled airway management, avoiding repeated intubation attempts that interrupt compressions or delay ventilation.
    2. 2Attempt intravenous access; consider intraosseous access if intravenous access cannot be achieved rapidly within two attempts.
    3. 3Give rhythm-appropriate ALS medicines and assess hypoxia, hypovolaemia, electrolyte or metabolic disturbance, hypothermia, thrombosis, tamponade, tension pneumothorax and toxins.
    4. 4Search concurrently for pre-eclampsia or eclampsia, puerperal sepsis, placental or uterine complications, and peripartum cardiomyopathy.
    5. 5Treat the cause immediately when identified, including haemorrhage control, anaphylaxis management or a toxicity-specific resuscitation pathway.
    03Resuscitative birthPrepare early and perform at the arrest siteOngoing maternal arrest in advanced pregnancy warrants uterine decompression as part of resuscitation.+
    1. 1Bring the skilled obstetric team and equipment to the woman and prepare from the start of the resuscitation response.
    2. 2Perform indicated resuscitative hysterotomy as soon as possible at the site of arrest; do not wait for a fixed four-minute mark or move to theatre for convenience.
    3. 3Continue maternal CPR and airway care during the procedure, keeping space and personnel organised around those essential functions.
    4. 4Do not delay for fetal heart assessment, ultrasound confirmation of viability or routine surgical preparation when these would postpone maternal rescue.
    5. 5Provide a separate newborn resuscitation team and continue maternal haemorrhage control and ALS after the uterus is emptied.
    04After ROSCStabilise and investigate recoverySpontaneous circulation returns after maternal cardiac arrest.+
    1. 1Secure ongoing oxygenation, ventilation and haemodynamic support and arrange appropriate critical-care admission.
    2. 2Investigate and treat the precipitating cause, reassess bleeding and consider the consequences of medicines and emergency procedures.
    3. 3Coordinate maternal cardiac, neurological and obstetric care with neonatal assessment, and provide a named clinician for family communication.
    Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
    Forms part of the standard adult ALS drug algorithm during maternal cardiac arrest.

    Adrenaline during standard adult cardiac arrest

    Give 1 mg intravenously or intraosseously as soon as possible in a non-shockable arrest, or after the third shock in a shockable arrest; repeat every 3–5 minutes while ALS continues.

    Use the correct arrest preparation and stop arrest dosing when circulation returns. This is not the dose for anaphylaxis with a pulse; specific toxicological arrests and highly monitored physiology-guided resuscitation may require modified expert protocols.

    Treats shockable arrest persisting or recurring despite appropriate defibrillation.

    Amiodarone for refractory VF or pulseless VT

    Give 300 mg intravenously after three shocks for persistent or recurrent VF or pulseless VT; give a further 150 mg after five shocks.

    Do not delay shocks or compressions to administer it. This bolus schedule is for cardiac arrest and differs from slower infusion treatment of a patient with a pulse.