Physiological dyspnea of pregnancy: This is the most common cause of shortness of breath in pregnancy, occurring due to the physiological changes of pregnancy, including increased blood volume, cardiac output, and the pressure exerted by the expanding uterus on the diaphragm.

Asthma: Pre-existing asthma can worsen during pregnancy due to hormonal changes and may cause shortness of breath.
Pneumonia: Pregnant women are at higher risk for complications from pneumonia, which can cause shortness of breath.
Pulmonary embolism (less common but important to consider): Although less common, pulmonary embolism is a significant concern in pregnancy due to the hypercoagulable state.
Anemia: Common in pregnancy, anemia can lead to shortness of breath due to decreased oxygen-carrying capacity.
Cardiomyopathy (peripartum cardiomyopathy): A rare but serious condition that occurs during the last month of pregnancy or within 5 months after delivery, leading to heart failure symptoms including shortness of breath.

Pulmonary embolism: Despite being less common, it is critical to consider due to its high mortality rate if missed.
Amniotic fluid embolism: A rare but catastrophic condition that can cause sudden onset of shortness of breath, hypotension, and cardiovascular collapse.
Placenta previa or abruption: Although primarily associated with bleeding, these conditions can also lead to acute blood loss and subsequent shortness of breath.
Preeclampsia with severe features: Can lead to pulmonary edema, causing shortness of breath.

Idiopathic pulmonary arterial hypertension: A rare condition that can worsen during pregnancy and cause 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: Although not exclusively a pregnancy-related condition, cystic fibrosis can complicate pregnancy and cause shortness of breath due to worsening lung function.