Many women feel this way in the third trimester, and often it is a very normal symptom of pregnancy.
As your uterus expands and presses up onto your diaphragm, the space for your lungs to expand shrinks a little. This can leave you feeling somewhat short of breath, especially while lying flat on your back or after strenuous activity. It is not normal to feel so short of breath that you are gasping for air, having chest pain, or can’t do basic activities like walking from one room to another. If this is the case, get in touch with your obstetric provider right away so they can rule out any concerning issues with your heart, lungs, or blood clots.