What is the best initial approach for a 28-week pregnant woman with mild shortness of breath (SOB) on exertion, a normal physical examination, and no pre-existing medical conditions?

Reassurance is Appropriate for Mild Exertional Dyspnea in Normal Pregnancy

For a 28-week pregnant woman with mild shortness of breath on exertion, a normal physical examination, and no pre-existing medical conditions, reassurance is the appropriate initial approach without pulmonary function testing. 1, 2

Why Reassurance is the Correct Answer

• Dyspnea is a normal physiological adaptation in pregnancy, occurring in approximately 50% of pregnant women on exertion and 20% at rest, according to the American College of Cardiology and other guideline societies 1, 3

• A normal physical examination effectively rules out the need for invasive testing in the absence of concerning features such as oxygen desaturation, tachypnea, abnormal lung sounds, or signs of cardiopulmonary compromise 1

• Pulmonary function testing is reserved for specific populations with severe respiratory disorders such as COPD, severe asthma, cystic fibrosis, or restrictive lung disease—not for healthy pregnant women with mild exertional dyspnea 2, 4

Physiological Basis for Dyspnea in Pregnancy

• Pregnancy causes reduced vital capacity and expiratory reserve volume in all women, suggesting a restrictive respiratory pattern that is physiologically normal 3

• These respiratory changes are expected adaptations and do not require diagnostic workup when the clinical examination is reassuring 1

Critical Red Flags That Would Change Management

Before providing reassurance, you must actively exclude concerning features that would require immediate evaluation:

• Symptoms requiring urgent workup: severe dyspnea at rest, chest pain (particularly pleuritic), syncope or presyncope, hemoptysis, palpitations, or unexplained hypotension 1

• Physical examination findings requiring further investigation: oxygen desaturation with exertion (SpO2 <95%), tachypnea at rest (>20 breaths/min), persistent tachycardia, abnormal lung auscultation, or unilateral leg swelling 1

• Maternal early warning criteria: systolic BP >160 mmHg, diastolic BP >100 mmHg, or heart rate >130 bpm 1

Important Context About Pulmonary Embolism Risk

While reassurance is appropriate for this patient, you must remain vigilant about pulmonary embolism:

• Pulmonary embolism remains the leading cause of pregnancy-related maternal death in developed countries, with an incidence of 1 per 1000 to 1 per 3000 deliveries 1

• Pregnancy creates a hypercoagulable state due to increased coagulation factors and decreased venous flow from uterine compression 1

• However, in the absence of red flag symptoms or examination findings, routine screening is not indicated 1

Physical Activity Recommendations

• Women with well-controlled mild-moderate respiratory symptoms who are asymptomatic should not restrict activity and should be encouraged to maintain moderate-vigorous physical activity 2, 4

• Pregnant women without contraindications should continue regular exercise, as this has been shown to improve outcomes 4, 2

Patient Counseling and Follow-Up

• Instruct the patient to seek immediate care if she develops chest pain, severe dyspnea at rest, palpitations, syncope, or signs of fluid overload 1, 2

• Schedule routine follow-up to reassess symptoms and ensure no progression 2

• Explain that mild exertional dyspnea is a normal pregnancy symptom that typically does not require intervention 1

Common Pitfall to Avoid

Do not order pulmonary function testing for healthy pregnant women with mild exertional dyspnea and normal examination findings. This represents unnecessary testing that will not change management and may cause unwarranted anxiety. Pulmonary function testing is only indicated for patients with severe respiratory disorders or uncontrolled symptoms 2, 4