The sudden cardiac arrest of a pregnant woman requires immediate intervention to support two lives. Standard cardiopulmonary resuscitation (CPR) protocols must be adapted to overcome a physiological challenge specific to advanced pregnancy: aortocaval compression. When the mother lies flat, the enlarged uterus presses on the major blood vessels (the inferior vena cava and the aorta). This pressure reduces the return of blood to the heart, making chest compressions ineffective unless this obstruction is relieved. A successful outcome depends entirely on performing high-quality CPR while incorporating a positional modification.
Initial Response and Standard Assessment
The first response involves confirming the woman’s lack of responsiveness and breathing. Immediately call emergency medical services (EMS), clearly stating that the patient is pregnant so the dispatcher can send appropriate resources. Rapid activation of the emergency system is important because pregnant patients have a reduced oxygen reserve compared to non-pregnant adults.
Position the woman flat on her back on a firm surface, such as the floor, to ensure effective chest compressions. This supine position, however, creates the challenge of aortocaval compression if the woman is visibly pregnant (typically past 20 weeks gestation). The initial goal is to establish the foundation for effective compressions while preparing to mitigate this circulatory challenge.
The Critical Modification: Manual Left Uterine Displacement
The key difference in CPR for a pregnant woman is the continuous need to relieve pressure on the major vessels using manual left uterine displacement (LUD). If the uterus is palpable at or above the navel, the weight of the fetus and uterus presses on the vena cava and aorta. Without LUD, the blood pumped by compressions cannot effectively return to the heart.
To perform manual LUD, the rescuer must use one or both hands to firmly push the woman’s abdomen and uterus toward her left side. This action shifts the weight off the maternal vessels, restoring blood flow to the heart. This displacement must be maintained without interruption for the entire resuscitation effort.
If a second rescuer is available, they should be dedicated solely to maintaining LUD while the first rescuer performs compressions. A solo rescuer places one hand on the woman’s right side, cupping the uterus, and pulling it toward the left while positioning the other hand for chest compressions. Manual displacement is preferred over placing a wedge under the right hip, as tilting can compromise the quality of chest compressions on a firm surface.
The success of the resuscitation hinges upon effective displacement, which improves the mother’s cardiac output by up to 30%. This maneuver ensures that the blood flow generated by chest compressions circulates effectively, reaching the mother’s vital organs and the placenta. Maintaining continuous LUD separates pregnant CPR from standard adult protocols.
Delivery of Chest Compressions and Rescue Breaths
Once left uterine displacement is maintained, the focus shifts to delivering high-quality chest compressions and rescue breaths. The mechanics remain the same as for any adult: position the heel of one hand in the center of the chest, on the lower half of the breastbone. The rescuer should aim for a depth of at least two inches (five centimeters) and a rate between 100 and 120 compressions per minute.
The standard compression location is not shifted higher on the chest, despite the enlarged abdomen. Compressions must be delivered hard and fast, allowing the chest to fully recoil between each compression to maximize blood flow. Minimizing interruptions is a priority, as pauses reduce the chance of survival.
The standard compression-to-ventilation ratio of 30 compressions followed by two rescue breaths should be used. Pregnant patients have a higher metabolic rate and decreased oxygen capacity, making rescue breaths important for adequate oxygen delivery to the mother and fetus. When administering breaths, a careful head-tilt/chin-lift is necessary to open the airway.
If an Automated External Defibrillator (AED) becomes available, use it immediately. Defibrillation is safe for pregnant women and should not be delayed due to concerns about the fetus. Apply the AED pads in the standard adult positions—one below the right collarbone and the other on the side of the left chest—following the voice prompts. Continue compressions and breaths, maintaining left uterine displacement, until EMS professionals arrive.