Cardiac Arrest in Pregnancy and Resuscitative Hysterotomy

Cardiac arrest in pregnancy means arrest in a patient who is pregnant or has recently given birth. You still resuscitate the mother first. The fetus does best when maternal CPR works. Resuscitative hysterotomy (perimortem cesarean delivery) is an added step, not a replacement for resuscitating the mother. The 2025 AHA guidance lists pregnancy among the adult special circumstances of resuscitation (Part 10).

Late in pregnancy, the gravid uterus presses on the inferior vena cava and aorta when the patient lies supine. Blood struggles to get back to the heart, and forward flow during CPR drops. So your compressions do less. Shift the uterus to the left and that pressure comes off.

• Common causes: the same causes as any adult arrest: acute coronary syndrome, arrhythmia, shock, hypoxia. Then add the pregnancy-specific ones: obstetric hemorrhage, hypertensive disorders with seizure, pulmonary embolism, amniotic fluid embolism and anesthetic complications.
• Two patients: run the maternal arrest pathway first. The newborn gets resuscitated at delivery, on the neonatal pathway.
• Outcomes are poor, and the data are thin: survival to discharge was 4.5% for mothers and 45.0% for newborns in out-of-hospital arrests treated with resuscitative hysterotomy. The 2025 systematic review covered 66 women and 68 neonates. Most of the publications were case reports (38 of 42), and certainty of evidence is very low.

Typical Presentation

• Collapse: sudden unresponsiveness with no pulse. It often happens at or after a known pregnancy stage: late second or third trimester, labor, or the first hours after birth.
• Preceding signs: watch for severe headache, visual change, seizure or a severe-range blood pressure, which point to preeclampsia. Heavy bleeding points to hemorrhage. Chest pain or sudden dyspnea points to pulmonary embolism. Sudden hypoxia or hypotension during labor, delivery or right after birth points to amniotic fluid embolism.

Red Flags

• Fundal height at or above the umbilicus, about 20 weeks of gestation: manual left uterine displacement from the start of CPR
• No return of circulation about 4 minutes after arrest despite high-quality CPR: begin resuscitative hysterotomy. Call the team and set up the kit from the start of arrest
• Severe-range BP (SBP 160 mmHg or higher, or DBP 110 mmHg or higher) with headache, visual change or seizure: preeclampsia with severe features is the likely cause. See Preeclampsia and Eclampsia
• Heavy bleeding before or after birth: see Postpartum Hemorrhage

Arrest is a clinical call, and you run the checks below during CPR. None of them may hold up compressions, displacement or defibrillation.

• Syncope or near-syncope with a pulse: lying flat, the gravid uterus can drop the blood pressure, and late in pregnancy that is common. A palpable pulse means this is not arrest. Turn the patient to the left and reassess.
• Pulmonary embolism: think PE when hypoxia, tachycardia and collapse come on suddenly. Reperfusion, by thrombolysis or mechanically, is a protocol decision made with medical direction. See Pulmonary Embolism
• Amniotic fluid embolism: sudden hypoxia, hypotension, and bleeding or coagulopathy during labor, delivery or in the first hours after birth. You reach it by ruling everything else out. Treat it as a cardiac arrest pathway and call the obstetric and ICU teams. The specific supportive steps are protocol-dependent.
• Peripartum cardiomyopathy and coronary causes: chest pain or arrhythmia before the collapse. Treat it as in adult cardiac arrest. See Adult Cardiac Arrest

1. Scene safety and recognition: confirm unresponsiveness and absence of normal breathing. Call for help, request the obstetric team if the patient is known to be pregnant, and bring an AED.
2. Start CPR: begin chest compressions at once, with the standard technique and rate for adults, and minimize interruptions.
3. Manual left uterine displacement: with the patient supine, push the uterus to the left to move it off the aorta and vena cava, while CPR continues. Use a left lateral tilt only if manual displacement is not possible, and accept poorer compressions.
4. Attach the AED or monitor-defibrillator: defibrillate shockable rhythms immediately and resume CPR at once. Shock indications and standard adult energy are unchanged in pregnancy. Do not delay or withhold a shock, and do not delay defibrillation to remove or read fetal monitoring.
5. Ventilate: give supplemental oxygen by bag-mask. Avoid excessive ventilation.
6. Transport priority: keep CPR going during the move, per protocol. Transport time has to be weighed against the hysterotomy window. A trained team that can start on scene, or a close facility, may be the faster option. Notify the receiving facility early, and ask the obstetric team to meet the patient. Decisions follow local protocol and medical direction.

Doses vary by protocol; follow local protocols and medical direction. Pregnancy doesn't alter the ACLS drug sequence. Run the adult cardiac arrest pathway for drugs and rhythms, and keep uterine displacement going the whole time.

• Access (Paramedic/RN/CCT): get IV access first, above the diaphragm when you can (arm or cubital vein). Avoid femoral or lower-extremity lines, since the gravid uterus impedes IVC flow. If IV access isn't quickly obtained, go intraosseous, using an upper-limb (humeral) site rather than a tibial site, per protocol. See IO Access.
• Epinephrine (Paramedic/RN/CCT): 1 mg (10 mL of 0.1 mg/mL) IV/IO every 3–5 min, as in adult cardiac arrest. Non-shockable rhythm: give it as soon as it's feasible. Shockable rhythm: wait until the initial defibrillation attempts have failed. See Epinephrine IV
• Shock-refractory VF/pVT (Paramedic/RN/CCT): amiodarone or lidocaine per the Adult Cardiac Arrest page and local protocol. Calcium, sodium bicarbonate and magnesium aren't routine in undifferentiated arrest. Reach for them only with a specific cause.
• Advanced airway: oxygenation comes first, because pregnant patients desaturate quickly. Give high-flow oxygen and bag-mask ventilation while you prepare. Pregnancy changes the airway with edema, reduced chest compliance and higher aspiration risk, so intubation gets harder. The most experienced operator available should manage the airway. Have a smaller endotracheal tube (6.0 to 7.0 mm) ready, with a supraglottic device as backup per protocol. Don't pause compressions longer than placement requires. After intubation, ventilate at 8 to 10 breaths per minute and avoid hyperventilation. Confirm placement with waveform capnography. See Intubation
• Hysterotomy decision (Paramedic/RN/CCT): your crew makes the calls, prepares and transports. Resuscitative hysterotomy is a physician or trained obstetric team procedure. Where EMS performs it in your system, follow the protocol and medical direction.

• Resuscitative hysterotomy: no return of circulation at about 4 minutes after arrest? Start the procedure with a trained team and aim for delivery within 5 minutes of arrest. Don't hold delivery for an operating room when it can be done at the bedside. Decisions follow local protocol and medical direction.
• After delivery: hand the newborn to the neonatal team at once. The newborn follows the Neonatal Resuscitation pathway.
• Cause-directed treatment: treat the cause. Reperfusion for pulmonary embolism. Hemorrhage per the Postpartum Hemorrhage page. Seizure and BP management per the Preeclampsia and Eclampsia page.
• Post-arrest care: the post-arrest care pathway sets the targets and the neuroprognostication for ROSC patients (see Adult Cardiac Arrest). That includes targeted temperature management for a comatose patient, and you avoid hyperthermia. While the uterus is at or above the umbilicus, keep it displaced to the left or position the patient in left lateral decubitus. Bring obstetrics in early for fetal assessment and delivery planning. Avoid hypotension and hypoxia.
• Extracorporeal support: ECPR is considered for selected refractory arrests, and only where the system has the infrastructure and selection criteria. Selection is protocol-dependent. See ECMO.
• Consults: call obstetrics, anesthesia, neonatology and critical care early. Involve the blood bank for massive hemorrhage.

• Destination: pick a facility with obstetric surgery, anesthesia, a blood bank and a neonatal intensive care unit. A ROSC patient with a suspected coronary cause goes to a PCI-capable center if that is the cause.
• In transit: keep CPR and manual left uterine displacement going, per protocol. Monitor EtCO₂, rhythm and SpO₂. Keep the airway secured. Field hysterotomy is protocol-dependent. It takes trained personnel and medical direction.
• If birth occurs in transit: the newborn is a separate patient. Use the neonatal resuscitation steps and keep the newborn warm.
• Handoff: time of arrest, start of displacement, time of any hysterotomy decision, drug times and doses, number of shocks, ROSC time, gestational age, and any bleeding history.

• Pediatrics: pregnant adolescents follow this adult pathway. The mother's drug doses are adult doses, not weight-based. The newborn follows the Neonatal Resuscitation page. Children who aren't pregnant follow the Pediatric Cardiac Arrest page and weight-based dosing.
• Pregnancy: maternal resuscitation comes first. Start manual left uterine displacement with CPR once the uterus is at or above the umbilicus (about 20 weeks). Resuscitative hysterotomy is considered if there is no return of circulation about 4 minutes after arrest, with delivery aimed for within 5 minutes. Usual ACLS drugs and shocks continue in pregnancy, per protocol. Avoid excessive ventilation.
• Hypertensive disorders: manage preeclampsia and eclampsia per the Preeclampsia and Eclampsia page. That covers magnesium and blood pressure control.
• Hyperkalemia and toxicology: cause-directed drugs follow the adult pathway. See Adult Cardiac Arrest.

• Error: starting CPR without manual left uterine displacement in a pregnant patient at or after about 20 weeks. Start both at once.
• Error: stopping compressions to reposition the patient or the uterus. Keep compressions going and adjust displacement as you work.
• Error: waiting for a second drug cycle before starting the hysterotomy. Call the team and set up the kit from the start of arrest. Begin at about 4 minutes if there is no ROSC, and aim for delivery within 5 minutes.
• Error: using methylergonovine for postpartum bleeding in a patient with hypertension or preeclampsia. It is contraindicated. See Postpartum Hemorrhage
• Error: giving routine calcium, sodium bicarbonate or magnesium in undifferentiated arrest. In eclampsia, magnesium toxicity can itself cause arrest. If magnesium sulfate was running before the arrest, stop the infusion and give calcium per protocol. See Magnesium Sulfate
• Error: placing drug access only in a femoral or other lower-extremity vein. The gravid uterus impedes IVC flow, so drugs may not reach the heart. Place access above the diaphragm.
• Error: getting the epinephrine concentration wrong. The arrest dose is 1 mg: 10 mL of 0.1 mg/mL (1:10,000). Confirm concentration and volume.