Dyspnea during pregnancy

Learning objectives

Describe the differences between physiological pregnancy-related dyspnea and pathological dyspnea
Diagnose and treat underlying conditions of dyspnea during pregnancy

Dyspnea is a common issue during pregnancy, caused by the physiological changes to the respiratory and cardiovascular systems
60 – 70% of pregnant women experience some form of dyspnea during the gestation period
Most often first noticed while conversing, being unable to complete a sentence without pausing to breathe
Distinguishing between physiological pregnancy-related dyspnea and pathological dyspnea can be challenging

Physiologically increased “need for breathing”, possibly caused by progesterone-induced stimulation of the respiratory center in the brain, body habitus, anemia, and increased pulmonary blood flow
Facilitates the increase in tidal volume needed due to the increased oxygen consumption

	Physiological dyspnea	Pathological dyspnea
Mechanisms	Possibly progresterone-induced hyperventilation, body habitus, anemia, increased pulmonary blood flow	Due to etiology
Onset	Gradual	Acute
Timing	Starts earlier in first/second trimester	Usually starts in second trimester
Progression	Plateaus or improves near term	Progressively worsens near term
Positional symptoms	Worst in sitting position	May not tolerate supine position
Exercise tolerance	Not associated with exercise	May be unable to perform daily activities
Physical findings	No wheeze and chest clear to auscultation	Abnormal pulmonary and/or cardiac findings

Cardiac	Cardiomyopathy
	Valvular heart disease (Aortic regurgitation, aortic stenosis, mitral regurgitation, mitral stenosis)
	Pulmonary hypertension & right ventricular failure
	Cardiac ischemia
	Congenital heart disease
	Arrythmias/heart block
	Pericardial (pericarditis/tamponade)
Respiratory	Infections
	Restrictive: interstitial lung disease, cystic fibrosis, neuromuscular disease, scoliosis
	Obstructive: asthma, COPD
	Pneumothorax
	Anaphylaxis (bronchospasm)
Pregnancy-specific	Severe preeclampsia/eclampsia
	Amniotic fluid embolism
	Pulmonary embolism
	Tocolytic induced pulmonary edema
	Peripartum cardiomyopathy
	High neuraxial blockade
Others	Anemia
	Hypothyroidism
	Hepatic dysfunction

Cause of dyspnea	Clinical signs	Diagnostic investigations	Treatment
Physiological	Need to take a deep breath intermittently, or inability to get a deep enough breath	None	Reassurance
Asthma/airway disease	Dyspnea with chest tightness or wheezing	Spirometry pre- and postbronchodilator	Inhaled beta-agonists ± inhaled steroids
Cardiac disease	Myocardial/valvular dysfunction: progressive orthopnea or orthopnea with paroxysmal nocturnal dyspnea Often present at end of second trimester or in early postpartum period when fluid shifts occur	Echocardiogram	Diuretics, beta-blockers as indicated, ACE inhibitors contraindicated in pregnancy
Arrhythmia	Sudden onset and cessation, associated sensation of palpitations or chest discomfort	Electrocardiogram, Holter or event monitor	Beta-blockers, calcium channel blockers
Venous thromboembolism	Sudden onset, any trimester May have associated deep venous thrombosis features	Computerized tomography pulmonary angiogram, V/Q scan, lower-extremity Dopplers	Anticoagulation with injectable heparins in pregnancy, warfarin in the postpartum period