Cardiac Arrest During Pregnancy: The ACLS Algorithm Every Young Doctor Should Know

A night-shift scenario: your 30-week pregnant patient collapses

This scenario is why a memorised drug list alone is not enough. As a house officer, medical officer or resident, you need to recognise your role, give clear instructions and prevent avoidable delays.

Why is CPR different during pregnancy?

In later pregnancy, the enlarged uterus may compress the inferior vena cava and aorta when the patient lies on her back. This can reduce blood returning to the heart and make chest compressions less effective. Pregnancy also increases oxygen demand and reduces respiratory reserve, making rapid oxygenation and skilled airway management especially important.

Cardiac arrest pregnancy algorithm: step-by-step ACLS approach

Use this bedside sequence as a learning aid alongside the 2025 AHA guidance for special circumstances and your hospital’s obstetric emergency protocol.

1. Recognise cardiac arrest and activate help. If the patient is unresponsive, has no normal breathing and has no definite pulse within 10 seconds, start CPR. Call the cardiac arrest team and alert obstetrics, anaesthesia and neonatal staff.
2. Provide high-quality CPR. Compress at 100–120/min, about 5–6 cm deep in an average adult, allowing full chest recoil. Minimise pauses. Without an advanced airway, trained rescuers use 30 compressions to 2 breaths.
3. Relieve aortocaval compression. If fundal height is at or above the umbilicus (often around 20 weeks or later), assign a team member to provide continuous manual left uterine displacement while compressions continue.
4. Check rhythm and defibrillate when indicated. Apply the AED/defibrillator. Shock VF or pulseless VT according to the standard adult arrest algorithm. Do not shock PEA or asystole. Pregnancy is not a reason to withhold an indicated shock.
5. Secure oxygenation and vascular access. Ask the most experienced available clinician to manage the potentially difficult airway. Avoid prolonged interruptions to CPR. Prefer upper-extremity IV/IO access rather than lower-extremity access.
6. Give standard ACLS treatment and fix the cause. Epinephrine is used according to the adult algorithm: 1 mg IV/IO every 3–5 minutes. Give it as soon as feasible for non-shockable arrest; in shockable arrest, prioritise initial defibrillation attempts. Look for haemorrhage, hypoxia, embolism, anaesthetic problems and other reversible causes.
7. Prepare for resuscitative delivery immediately when indicated. With fundal height at or above the umbilicus, the obstetric team begins preparation at recognition of arrest—not after several minutes have passed. If ROSC is not achieved, aim to complete delivery by 5 minutes, with ongoing resuscitation.
8. Continue advanced life support and coordinated care. After ROSC, stabilise the patient, treat the cause and coordinate ICU and obstetric care. If delivery occurs, a separate neonatal team follows neonatal resuscitation guidance.

ACLS rhythms in pregnancy: what should you do?

Throughout every pathway, continue pregnancy-specific actions such as uterine displacement when indicated and immediate team preparation for possible delivery. If ECG interpretation is an area you want to improve, explore the ECG and pharmacology preparation course.

The 5-minute goal: when is resuscitative delivery needed?

The 2025 AHA recommendations advise resuscitative delivery when the uterine fundus is at or above the umbilicus and ROSC has not been achieved with standard resuscitation. The main purpose is to help resuscitate the pregnant patient by relieving aortocaval compression. Potential benefit to the baby is important, but it is not the only reason for delivery.

You may have heard the older “4-minute rule.” It refers to the traditional approach of initiating delivery at about 4 minutes to achieve delivery by 5 minutes. Current guidance is to begin preparation as soon as the arrest is recognised. The team must not wait until minute four to make the first call.

Fundal height is the practical trigger, not a rigid gestational-age cut-off. The umbilicus often corresponds to approximately 20 weeks, but gestational dating and clinical findings can differ.

Reversible causes of maternal cardiac arrest

Pregnant patients can arrest from the usual adult causes, such as hypoxia, hypovolaemia, electrolyte problems or thrombosis. They can also have obstetric emergencies. The AHA pregnancy-specific causes framework can be remembered as A–H:

What if your patient is receiving magnesium sulfate?

If a pregnant patient develops cardiac arrest while receiving an IV magnesium sulfate infusion, the AHA pregnancy algorithm advises stopping magnesium and administering calcium. The resuscitation team should follow its local medication protocol and investigate the cause. Do not delay CPR or defibrillation while doing so.

What if amniotic fluid embolism is suspected?

Call for immediate obstetric and critical care support and activate a massive transfusion protocol when appropriate. Management is specialised and should follow the institutional emergency pathway. During maternal cardiac arrest, fetal monitoring should be stopped and fetal monitors detached because they interfere with priorities and offer no benefit during the arrest.

Five mistakes new doctors should avoid

1. Delaying CPR while waiting for a senior doctor. Start high-quality CPR and call for help simultaneously.
2. Forgetting the uterus. Assign one person to continuous left uterine displacement when the fundus is at or above the umbilicus.
3. Treating every rhythm as shockable. VF/pVT require defibrillation; PEA/asystole do not.
4. Waiting until four minutes to call obstetrics. Preparation for delivery begins immediately when the fundal criterion is met.
5. Focusing on fetal monitoring during maternal arrest. Prioritise effective maternal resuscitation and specialist obstetric/neonatal teamwork.

How to divide tasks in a real code

A practical team has a resuscitation leader, CPR providers, a clinician dedicated to uterine displacement, an airway lead, a defibrillator/medication clinician, an obstetric delivery team and a neonatal team. In smaller facilities, people may cover more than one role. Calling for support early is essential.

Why should Pakistani doctors learn BLS and ACLS?

For a new house officer in Lahore, an MO applying to a hospital in Rawalpindi, or a resident preparing for work in Islamabad, resuscitation skills are directly relevant to emergency calls. These skills also matter when considering clinical work in the Gulf, UK, US or elsewhere—although qualification and certification rules differ by employer and country.

BLS develops the ability to recognise cardiac arrest, perform quality CPR, use an AED and respond to choking emergencies. ACLS builds on that foundation with rhythm interpretation, adult cardiac arrest pathways, airway management, medications and team leadership. Pregnancy-specific training builds further on these foundations because maternal arrest requires obstetric coordination and additional procedures.

Are BLS and ACLS certificates mandatory for hospital induction or work abroad?

Sometimes—but not universally. Individual hospitals, emergency/critical-care roles, training programmes and employers may require current BLS and/or ACLS certification. The registration information on this website advises a current BLS Provider Card before ACLS attendance. However, BLS/ACLS should not be described as an automatic requirement for every PLAB, USMLE, FCPS, NHS or international job application. Check the latest official criteria of the institution or recruitment body you are applying to.

An AHA course credential documents successful completion of the relevant provider training. It does not replace medical licensing, registration, employer credentialing, postgraduate assessments or specialised maternal/neonatal resuscitation training.

If you also work in paediatric emergency care, the PALS course information may be relevant. Remember: PALS is not a substitute for a dedicated neonatal resuscitation programme when caring for a baby delivered during a maternal arrest. For experienced clinicians considering a teaching pathway, see instructor and training-centre registration information.

Frequently asked questions about cardiac arrest in pregnancy