Understanding Maternal Cardiac Arrest in the BLS Context
What Counts as Maternal Cardiac Arrest and When It Occurs
Maternal cardiac arrest (MCA) refers to the sudden cessation of circulation in a pregnant patient. It typically occurs during the second or third trimester but can also happen immediately postpartum. Causes range from trauma and embolism to eclampsia and cardiac complications. Each moment of delay drastically reduces both maternal and fetal survival. The AHA BLS for Healthcare Providers Course provides foundational skills that can be adapted to meet these rare challenges. BLS responders must treat maternal arrest as more than a variation of adult CPR. Their ability to recognize and act decisively makes the difference between life and loss in these critical cases.
Why Standard Adult Protocols Fall Short in Third-Trimester Patients
Third-trimester physiology alters everything from oxygen demand to circulation. The gravid uterus compresses the inferior vena cava, reducing venous return. This impacts cardiac output and oxygen delivery during resuscitation. Additionally, the diaphragm elevates, shifting the heart’s position and limiting lung expansion. Standard CPR hand placement and airway management must be adapted to reflect these anatomical changes. Ignoring these factors reduces the effectiveness of compressions and ventilation, even when performed with ideal technique.
When BLS Responders Become the Only Trained Providers on Scene
In many settings, especially rural or resource-limited areas, BLS responders arrive long before ALS units. This leaves you to manage the full burden of care. Without advanced tools or medications, your techniques must be flawless and well-practiced. This includes early CPR, AED usage, and manual uterine displacement. Waiting for ALS is not an option. Delivering modified, high-quality BLS in the first critical minutes often determines whether the patient regains spontaneous circulation—or not.
Identifying the Pregnant Patient in Distress—Before It’s Too Late
Visual Signs in Chaotic Scenes: What Clues Suggest Third-Trimester Pregnancy
Visual cues may be subtle or obscured by clothing or trauma. Look for a rounded lower abdomen, stretched fabric, or maternity-related medical tags. In crash or assault scenarios, the patient’s position may hide pregnancy indicators. Train yourself to scan for signs during the initial assessment. If you’re unsure, treat the patient as potentially pregnant until proven otherwise. It’s safer to assume pregnancy than to miss a time-sensitive intervention like left uterine displacement.
Common Missteps: Focusing on Trauma Without Realizing Pregnancy
Multisystem trauma draws attention. Bystanders may focus on bleeding or visible injury. Providers often do the same. In this chaos, pregnancy is easy to overlook—especially when the patient is unconscious. If abdominal injury is present, pregnancy may worsen internal bleeding or mask fetal compromise. Always consider pregnancy when treating females of childbearing age. Prioritize a quick abdominal assessment and ask questions if others are present.
How to Speak to Bystanders or Family to Confirm Gestation Rapidly
Time is limited, but dialogue can still provide critical insight. Ask concise questions like “Do you know how far along she is?” or “Was she pregnant?” Family or coworkers may offer a gestational week or trimester. If they can’t confirm, proceed with care as if the patient is pregnant. A single answer can shift your entire care plan, so don’t skip the chance to ask.
Assessing for Fetal Movement or Fundal Height When Unresponsive
In unresponsive patients, you may need to assess without verbal confirmation. Palpate the abdomen for a firm uterine fundus rising above the navel. If present, the patient is likely past 20 weeks gestation. Document any signs of movement, but don’t delay care to look for them. Treat based on what you observe, not what you guess.
High-Quality Chest Compressions on the Pregnant Patient
Correcting Hand Placement: Why the Sternum Landmark Shifts Upward
In late pregnancy, the diaphragm and heart sit higher than normal. This anatomical shift requires modified hand placement. Compress 1–2 inches above the standard mid-sternum location. Position your hands over the lower half of the sternum—but not near the xiphoid. If placement feels awkward, recheck landmarks. Your goal remains straight-down, consistent compressions that move blood—not just motion on the chest.
Depth, Rate, and Recoil Expectations Remain Unchanged—But Application Differs
Continue compressions at a rate of 100 to 120 per minute, aiming for 2-inch depth. Full chest recoil remains essential. Tilt the patient slightly to the left if possible. This improves venous return and prevents organ compression. Ensure compressions aren’t angled or offset, which often happens when working around a gravid abdomen. Use a stool or kneel properly to maintain a 90-degree angle.
Real-World Tips for Managing Abdominal Resistance or Breast Interference
Large breasts or abdominal swelling can hinder your mechanics. Move breasts aside to allow clear pad placement and compression access. Use a wedge or tightly rolled towel to angle the patient’s torso leftward. This helps displace the uterus while giving you better leverage. Avoid leaning across the abdomen or compressing from the side.
Positioning a Firm Surface Under the Patient in Transport or on Scene
Effective compressions require a firm base. On scene, use a CPR board, backboard, or even a collapsed wheelchair if needed. On stretchers, flatten the bed completely. Reassess hand position after every move or lift. Even minor shifts can affect compression quality. Confirm visible chest rise during ventilations to ensure you’re delivering adequate volume.
Manual Left Uterine Displacement (LUD): Technique Every BLS Provider Must Know
Why Uterine Displacement Increases Perfusion—and When It’s Lifesaving
After 20 weeks gestation, the uterus can compress both the aorta and inferior vena cava. This limits blood return to the heart, even with perfect CPR. Manual left uterine displacement improves preload and increases the likelihood of ROSC. Initiate it as soon as pregnancy is suspected. Evidence shows improved maternal survival when displacement is performed continuously during CPR.
Performing LUD Manually with One Hand While Assisting CPR
To perform manual displacement, kneel on the patient’s left. Use your right hand to push the uterus laterally toward the patient’s left side. Apply steady, firm pressure. Do not press downward. Use the flat of your hand, not fingertips. Keep the uterus shifted left throughout CPR to maximize its effect.
Coordinating LUD with Compressions in a Two-Rescuer Setup
Ideally, one rescuer manages compressions while another performs LUD. This prevents interruptions or fatigue-related shifts. Communicate clearly: “I’m on LUD,” or “Switch in two minutes.” Practice this choreography during training so roles feel intuitive. In limited teams, alternate roles to reduce physical strain.
Switching Hands or Roles When Fatigue Sets In
Even experienced providers lose pressure or angle over time. Rotate every two minutes or sooner if needed. If your hand slips, reposition carefully without losing compression rhythm. Assign backups or pre-train your team to perform LUD effectively under stress.
AED Use in Maternal Arrest: Facts, Myths, and Field Constraints
AED Safety During Pregnancy: Evidence-Based Reassurance for Providers
Defibrillation is both safe and necessary in pregnant patients. It poses no increased risk to the fetus. Shockable rhythms require immediate action. Never delay defibrillation because of pregnancy concerns. Bystanders or coworkers may hesitate—reassure them with facts.
Where to Place Pads When the Abdomen Is Enlarged or Breasts Are Prominent
Use standard anterolateral placement unless positioning is obstructed. Place one pad on the upper right chest, the other on the lower left rib cage. Lift the breast if necessary. Avoid placing pads directly over the uterus or belly. Ensure solid skin contact and press pads firmly before activating the device.
What to Do If the Patient Is Wet, Diaphoretic, or Has a Medication Patch
Moisture on the chest can reduce shock efficacy. Wipe sweat or water with a towel before pad placement. Remove any patches—especially nitroglycerin or hormone treatments—and clean the site. Avoid placing pads over jewelry, piercings, or scar tissue.
Managing Clothing Removal and Privacy in Public Scenes
Expose the chest quickly, even if the setting feels public. Assign someone to shield the patient with a blanket or turnout jacket. Protecting dignity doesn’t mean delaying care. Make eye contact with bystanders and explain the need for action confidently.
Understanding the Role of BLS vs ALS in Maternal Cardiac Arrest
| Action/Skill | BLS Provider | ALS Provider |
|---|---|---|
| Initiate High-Quality CPR | ✅ Yes — start immediately, modified for pregnancy | ✅ Yes — continues with advanced support |
| Manual Left Uterine Displacement | ✅ Yes — critical BLS role post-20 weeks | ✅ Yes — often continued during interventions |
| Use of AED | ✅ Yes — do not delay defibrillation | ✅ Yes — defibrillator with manual override |
| Oxygen & Basic Airway Adjuncts | ✅ Yes — BVM, OPA, NPA | ✅ Yes — advanced airway, ET tube, waveform capnography |
| Medication Administration | ❌ No — not within BLS scope | ✅ Yes — epinephrine, magnesium, etc. |
| Emergency C-Section or OB Procedure | ❌ No — never performed by BLS | ❌ Rare — only in hospital with surgical team |
BLS Team Dynamics in Maternal Cardiac Arrest
Assigning Roles Quickly: Compressor, LUD Tech, AED Lead, Airway Support
In a four-person team, assign roles immediately. One compresses. One performs LUD. One operates the AED. One supports the airway. If limited to two providers, alternate roles every two minutes. Don’t wait for command hierarchy—act on what the patient needs.
Coordinating Care While Awaiting ALS Without Freezing Care
Continue BLS uninterrupted while ALS units approach. Assign one person to update ALS upon arrival. Keep compressions and LUD going. Briefing should never cause a pause. A moving handoff ensures better transition and preserves compression fraction.
When Bystanders Can Help (and When They Shouldn’t)
Untrained bystanders can shield privacy or call out times. Only assign medical tasks like compressions or AED if they’ve had formal training. Never allow them to perform LUD or ventilation unless certified and competent. Use your judgment and speak clearly.
Using Your Rhythm Timer to Guide Compressions and Team Switches
Use a phone timer or AED metronome to pace compressions. Announce “two minutes!” to signal rotations. Rotate duties even when energy feels high. Fatigue drops performance long before it’s visible. Frequent switches preserve quality—and save lives.
Supporting ROSC While Preparing for Rapid Transport
How ROSC Presents in Pregnancy and What Vitals May Look Like
Signs of return of spontaneous circulation (ROSC) can be subtle in pregnancy. Expect shallow spontaneous breaths, improved skin color, or a palpable pulse at the carotid. Blood pressure may remain low initially. Confirm ROSC with two-person pulse checks lasting no more than 10 seconds. Always double-check before stopping compressions. Restart CPR immediately if doubts remain.
Continued LUD After ROSC: When and How Long to Maintain
Left uterine displacement should continue even after ROSC. Uterine pressure on the vena cava can still reduce venous return. Maintain manual displacement until the patient is loaded and positioned with a proper left lateral tilt. In some transports, the uterus shifts during motion. Re-check frequently.
Airway Reassessment and O2 Management for BLS Providers
After ROSC, reassess airway patency. Insert an OPA or NPA as appropriate. Deliver oxygen via non-rebreather or continue BVM if the patient remains apneic. Look for signs of regaining consciousness. Maintain oxygenation to preserve maternal and fetal perfusion until ALS takes over.
Prioritizing Fetal Monitoring Only After Maternal Stabilization (and at Hospital)
Fetal viability depends on maternal stability. Do not attempt fetal assessment or Doppler auscultation in the field. Focus on the mother’s perfusion, ventilation, and circulation. Once ALS arrives or the patient reaches the hospital, OB specialists will assess fetal heart tones.
Preventable Errors and BLS Scope Violations to Watch For
Skipping LUD Because It “Feels Weird” or “Seems Advanced”
Left uterine displacement is absolutely within BLS scope. Some providers hesitate, assuming it’s an ALS-only skill. That’s false. The intervention is mechanical, not pharmacologic. Failing to displace the uterus can reduce CPR effectiveness by nearly 30 percent. When in doubt—displace.
Delaying Defibrillation Due to Uncertainty Around Pregnancy
Don’t wait. Pregnancy is not a contraindication for AED use. Delayed shocks reduce survival chances dramatically. AEDs do not harm the fetus and may be the only tool that restores circulation. Shock when advised—without hesitation.
Attempting Medications or Maneuvers Outside BLS Protocol
Stick to what you’re trained for. Administering epinephrine or performing advanced airway techniques outside your license is not only dangerous—it’s illegal. Instead, perfect the basics. Execute compressions, displacement, AED, and airway skills with precision.
Overreliance on Arriving ALS While Compressions Stall
ALS arrival doesn’t mean you pause. Keep compressions going during handoff. Assign one provider to give a brief verbal report without interrupting care. A five-second delay can cost 20 percent of perfusion. Lead by example.
When the Baby Is Born Mid-Call: What Can BLS Do?
Recognizing Imminent Delivery During CPR or ROSC
Sudden crowning, spontaneous delivery, or vaginal bleeding may occur during resuscitation. If the baby presents, assist carefully while maintaining maternal support. Alert receiving staff immediately. Record time and delivery details accurately.
When to Assist vs When to Leave Delivery to Higher Care
If the baby is partially delivered or crowning, assist. If no visible delivery signs are present, continue resuscitation without attempting delivery. Forceful pulling or pushing is never appropriate. Prioritize CPR and uterine displacement until birth occurs naturally.
Basic Newborn Support Within BLS Scope: Drying, Stimulation, Clearing Airway
If a newborn is delivered, dry them immediately. Stimulate by rubbing the back or flicking the soles of the feet. Suction only if meconium or fluids obstruct the airway. Wrap the infant to preserve body heat and monitor breathing closely.
How to Manage Maternal Care While Newborn Resuscitation Begins
Assign another team member to manage the infant while CPR continues on the mother. If short-staffed, prioritize maternal care until ALS arrives. Make space for both patients and document care accurately. Dual-patient scenarios require calm, deliberate teamwork.
Integrating This Knowledge into Your BLS Practice
Which Protocol Books Include Maternal Arrest Guidance (State/Local Examples)
Many Florida EMS protocols include specific maternal arrest guidelines. These often reference LUD, AED use, and OB handoff procedures. Check your agency’s protocol book annually. Some services issue OB-specific quick guides in trauma kits or obstetric bags.
How Often to Re-Review Maternal Arrest Scenarios During Recertification
Include maternal arrest in your CPR refreshers—even if not explicitly required. Practice responding to a third-trimester code using real-time drills. Repeat exposure builds automaticity. Bring up the scenario during skill labs or review sessions with your instructor.
The Value of High-Fidelity Manikins and Scenario-Based Drills
Simulation labs often include OB-compatible manikins. These may include fundal height, fetal positioning, and delivery models. Practicing uterine displacement, CPR, and newborn management with these tools creates muscle memory. Request scenario-based training during your BLS renewal if available.
Where BLS Ends and ALS Begins: Advocating for Your Patient While Staying in Scope
Know your limits—but also know your value. Hand off clearly to ALS and stay engaged. Help with equipment, guide them on your sequence of care, and maintain LUD until relieved. Don’t try to “do more”—focus on doing your job right.
Staying Calm When Every Second Counts
Mental Checklists: What to Default to When Everything Feels Chaotic
Use a mnemonic if needed: Check responsiveness, Call 911, Start compressions, Displace uterus, Apply AED. Repeat. These core steps prevent you from freezing. Stay in motion, keep breathing, and trust your training.
Why Pre-Planning Team Roles in Advance of Calls Matters
Discuss rare-call strategies during team huddles or down time. Decide who leads airway, who runs compressions, and who handles displacement during OB codes. Pre-defined roles reduce hesitation and help teams perform faster under pressure.
Confidence Through Muscle Memory: How to Make MCA Part of Every BLS Team Drill
Drill maternal arrest scenarios every quarter. Use manikins or mock drills. Practice switching roles, managing two patients, and delivering uninterrupted care while ALS arrives. With repetition, nerves fade—and skill rises.
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