Learning objectives
- Describe the differences between physiological pregnancy-related dyspnea and pathological dyspnea
- Diagnose and treat underlying conditions of dyspnea during pregnancy
Background
- 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
Physiological dyspnea
- 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
Pathological dyspnea
- Key differences with physiological dyspnea:
| 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 |
- Differential diagnosis:
| 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 |
Diagnosis & treatment
| 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 |
Suggested reading
- Mehta N, Chen K, Hardy E, Powrie R. Respiratory disease in pregnancy. Best Pract Res Clin Obstet Gynaecol. 2015;29(5):598-611.
- Hegewald MJ, Crapo RO. Respiratory physiology in pregnancy. Clin Chest Med.
