What is the best initial approach for a 28-week pregnant patient with mild shortness of breath (SOB) on exertion and a normal exam?

Management of Mild Exertional Dyspnea at 28 Weeks Gestation

Reassurance is the appropriate initial approach for this patient, as mild shortness of breath on exertion with a normal physical examination is a common physiological adaptation to pregnancy and does not warrant pulmonary function testing. 1

Clinical Reasoning

Why Reassurance is Appropriate

• Physiological dyspnea is extremely common in normal pregnancy, affecting the majority of pregnant women, and is difficult to differentiate from pathological causes based on symptoms alone 2, 3
• The normal physical examination is key – this patient lacks red flags such as oxygen desaturation, tachypnea, abnormal lung sounds, or signs of cardiopulmonary compromise 1
• Mild exertional dyspnea at 28 weeks with normal exam findings falls within the expected physiological changes of pregnancy and does not meet criteria for further diagnostic workup 1

When Pulmonary Function Testing is NOT Indicated

• Pulmonary function testing is reserved for patients with severe respiratory disorders such as COPD, severe asthma, cystic fibrosis, or restrictive lung disease 1
• This patient has no prior medical conditions and therefore does not meet criteria for PFT 1
• A normal physical examination effectively rules out the need for invasive testing in the absence of concerning features 1

Critical Red Flags to Exclude

While reassurance is appropriate here, you must actively assess for pathological causes that would change management:

Symptoms Requiring Immediate Evaluation

• Severe dyspnea at rest (not just mild exertional dyspnea) 1
• Chest pain, particularly pleuritic chest pain 4
• Syncope or presyncope 4, 1
• Hemoptysis 4
• Palpitations or unexplained hypotension 4, 1

Physical Examination Findings Requiring Workup

• Oxygen desaturation with exertion (SpO2 <95%) 1
• Tachypnea at rest (>20 breaths/min) 4
• Persistent tachycardia (though mild tachycardia can be normal) 4
• Abnormal lung auscultation 5
• Unilateral leg swelling (DVT is more common in left leg during pregnancy) 4, 5

Important Context About PE Risk

Why PE Must Be Considered in Pregnancy

• Pulmonary embolism remains the leading cause of pregnancy-related maternal death in developed countries, with incidence of 1 per 1000 to 1 per 3000 deliveries 4, 5
• Pregnancy creates a hypercoagulable state due to increased coagulation factors and decreased venous flow from uterine compression 4, 5
• However, 90% of patients with PE have dyspnea AND tachypnea together – isolated mild exertional dyspnea with normal vital signs makes PE unlikely 4

When to Pursue PE Workup

• Do NOT rely on D-dimer alone – sensitivity is only 73% and specificity 15% in pregnancy, making it inadequate to rule out PE 4
• If PE is suspected clinically, start with bilateral lower extremity compression ultrasound to look for DVT, as finding DVT warrants anticoagulation without further testing 4, 5
• Chest X-ray and arterial blood gas (in upright position) can help risk-stratify, though normal results do not exclude PE 4, 5

Patient Counseling and Follow-Up

Reassurance Points

• Encourage continued moderate physical activity – pregnant women without contraindications should maintain moderate-vigorous physical activity 1
• Women with well-controlled mild-moderate respiratory symptoms who are asymptomatic should not restrict activity 1

Return Precautions

• Instruct the patient to seek immediate care if she develops:
  • Chest pain of any type 1
  • Severe dyspnea at rest 1
  • Palpitations or syncope 1
  • Signs of fluid overload (orthopnea, paroxysmal nocturnal dyspnea) 1

Ongoing Monitoring

• Schedule routine follow-up to reassess symptoms and ensure no progression 1
• Re-evaluate if symptoms worsen or new concerning features develop 1

Common Pitfall to Avoid

The major pitfall is dismissing ALL dyspnea as "normal in pregnancy" without proper assessment. While mild exertional dyspnea with normal exam is reassuring, you must actively exclude red flags at each visit, as pregnancy-related PE can be fatal and symptoms overlap significantly with normal pregnancy 4, 5. The key differentiator is the combination of mild symptoms, exertional pattern only, and completely normal physical examination – this constellation supports reassurance over testing.