Differential Diagnosis for Shortness of Breath in Pregnancy

When considering shortness of breath in pregnancy, it's crucial to approach the diagnosis systematically, taking into account the physiological changes of pregnancy and the potential for pregnancy-specific conditions, as well as non-pregnancy related causes. The differential diagnoses can be categorized as follows:

• Single Most Likely Diagnosis

  • Physiological dyspnea of pregnancy: This is the most common cause of shortness of breath in pregnant women, resulting from the physiological changes of pregnancy, including increased blood volume, cardiac output, and the pressure exerted by the expanding uterus on the diaphragm. It typically presents in the second and third trimesters.

• Other Likely Diagnoses

  • Asthma: Pre-existing asthma can worsen during pregnancy due to hormonal changes and may require adjustment of treatment.
  • Anemia: Common in pregnancy due to increased blood volume and demand for iron, leading to a decrease in oxygen-carrying capacity.
  • Pulmonary embolism (though more considered under "Do Not Miss"): While less common, it's a critical diagnosis to consider due to the increased risk of thromboembolism in pregnancy.
  • Cardiomyopathy (peripartum cardiomyopathy): A rare but potentially life-threatening condition that occurs during the last month of pregnancy or within 5 months after delivery.

• Do Not Miss Diagnoses

  • Pulmonary embolism: Although less likely, it is critical to rule out due to its high mortality rate if untreated. Pregnancy increases the risk of venous thromboembolism.
  • Pneumonia: Can present with shortness of breath and is a significant concern in pregnancy due to the potential for severe disease.
  • Amniotic fluid embolism: A rare but catastrophic condition that can cause sudden onset of shortness of breath, among other symptoms.
  • Placenta previa or abruption: While primarily associated with bleeding, these conditions can also lead to acute blood loss and subsequent shortness of breath.

• Rare Diagnoses

  • Idiopathic pulmonary arterial hypertension: A rare condition that can be exacerbated by pregnancy, leading to severe shortness of breath.
  • Lymphangioleiomyomatosis: A rare lung disease that can cause shortness of breath and is more commonly diagnosed in women of childbearing age.
  • Cystic fibrosis: A genetic disorder that can cause respiratory symptoms, including shortness of breath, and may first be diagnosed or worsen during pregnancy.

Each of these diagnoses requires careful consideration of the patient's history, physical examination, and appropriate diagnostic testing to ensure accurate diagnosis and management. The justification for each includes the pathophysiological changes of pregnancy, the prevalence of these conditions in the pregnant population, and the potential impact on both mother and fetus.