What is the management of near syncope (presyncope) in pregnancy?

Management of Near Syncope (Presyncope) in Pregnancy

Immediately position the pregnant patient in left lateral decubitus position or assist her to lie down safely, as this addresses both the pregnancy-specific supine hypotensive syndrome and prevents injury from progression to syncope. 1

Immediate First Aid Management

Initial Positioning (Critical First Step)

• Place the patient in left lateral decubitus position to relieve aortocaval compression from the gravid uterus, which is a pregnancy-specific cause of presyncope 1
• If left lateral position is not immediately feasible, assist the patient to sit or lie down in any safe position to prevent injury from potential syncope 1
• Positioning must occur within 1-2 minutes of symptom onset 1

Physical Counterpressure Maneuvers (After Safe Positioning)

Once the patient is safely positioned, physical counterpressure maneuvers (PCMs) can be beneficial to abort progression to syncope if symptoms are vasovagal or orthostatic in origin 1:

Lower-body PCMs (preferred): 1

• Leg crossing with tensing of leg, abdominal, and buttock muscles
• Squatting position with muscle tensing
• These are more effective than upper-body maneuvers 1

Upper-body PCMs (alternative): 1

• Arm tensing by gripping opposing hands and pulling
• Isometric handgrip with maximum fist clenching
• Neck flexion with muscle tightening

Critical Exclusions for PCMs

Do NOT use physical counterpressure maneuvers if the patient has: 1

• Chest pain or symptoms suggesting myocardial infarction
• Focal neurological symptoms suggesting stroke
• Any signs of hemodynamic instability

Risk Stratification and Urgent Evaluation

High-Risk Features Requiring Emergency Services Activation

Activate emergency services immediately if: 1, 2

• No improvement within 1-2 minutes of positioning 1
• Syncope actually occurs 1
• Symptoms worsen or recur 1
• Presyncope occurred during exertion 2
• Patient has palpitations preceding the episode 2
• History of structural heart disease or heart failure 2
• Family history of sudden cardiac death 2

Pregnancy-Specific Life-Threatening Causes to Consider

While vasovagal syncope and orthostatic hypotension are the most common benign causes in pregnancy, life-threatening etiologies must be excluded: 2

• Pulmonary embolism 2
• Cardiac arrhythmias 2
• Amniotic fluid embolism 2
• Ruptured ectopic pregnancy (if early pregnancy) 3

Diagnostic Evaluation

Mandatory Initial Assessment

All pregnant patients with presyncope require: 2

• 12-lead ECG - noninvasive, inexpensive, identifies life-threatening conditions immediately despite low 5% yield 2
• Look specifically for: myocardial ischemia, arrhythmias, conduction abnormalities, prolonged QT interval, ventricular hypertrophy, pre-excitation patterns 2

Orthostatic vital signs: 2

• Measure blood pressure and heart rate supine and after standing
• Abnormal if systolic BP drops >20 mmHg or heart rate increases >20 bpm 2

Focused history elements: 2

• Structural heart disease or heart failure history 2
• Family history of sudden cardiac death 2
• Circumstances of the episode (exertion, position, prodromal symptoms) 2
• Palpitations before the event 2

Pregnancy-Specific Physiologic Context

Normal pregnancy changes that predispose to presyncope include: 2

• Increased cardiac output 2
• Decreased systemic vascular resistance 2
• Aortocaval compression by gravid uterus 2
• These explain why left lateral positioning is critical 1

Disposition and Follow-Up

Safe for Outpatient Management

Patients can be discharged with obstetric follow-up if: 2

• No structural heart disease 2
• Normal ECG 2
• Clinical features clearly suggesting vasovagal or orthostatic syncope 2
• No high-risk features present 2

Requires Admission or Urgent Cardiology Evaluation

Admit or arrange immediate cardiology consultation for: 2

• Age >45 years 2
• History of heart failure or ventricular arrhythmias 2
• Abnormal ECG 2
• Physical exam findings of heart failure 2
• Cardiac murmur suggesting outflow obstruction 2
• Patients with 3-4 risk factors have 57.6-80.4% risk of 1-year mortality or significant arrhythmia 2

Special Considerations

Supine Hypotensive Syndrome

This pregnancy-specific syndrome occurs when: 1

• The gravid uterus compresses the inferior vena cava 1
• Venous return decreases, causing paradoxical sinus slowing and hypotension 1
• Management is simply changing position to left lateral decubitus 1
• If symptoms persist despite positioning, temporary pacing may be necessary 1

Common Pitfalls

• Dismissing presyncope as less serious than syncope - both have similar short-term serious outcomes and mortality rates and should be evaluated identically 4
• Failing to position pregnant patients in left lateral decubitus - this addresses a reversible pregnancy-specific cause 1
• Using PCMs when cardiac or stroke symptoms are present - this is contraindicated and potentially dangerous 1
• Not obtaining an ECG - this simple test can identify life-threatening cardiac causes 2