The increased body burden after pregnancy may cause physiological chest tightness and shortness of breath, especially after activity, and may also have slight dyspnea, but it can be relieved after rest. However, certain diseases such as hypertensive disorders during pregnancy, pregnancy combined with heart disease can also cause pregnant women to have symptoms of dyspnea and shortness of breath. I. Physiological reasons 1, the increase in circulating blood volume: the increase in circulating blood volume after pregnancy, at this time, pregnant women can show dyspnea, chest tightness and shortness of breath, which can increase by 1/3-1/4 compared to the non-pregnant period, adapting to the increased blood flow in the uterus placenta and various tissues and organs, which is extremely important to maintain the growth and development of the fetus; 2, increased cardiac output: the increase in circulating blood volume will make the heart more burdened. At the same time, in late pregnancy, the uterus will make the diaphragm elevated, the heart is displaced upward, blood flow increases, blood flow speed accelerates, the heart burden increases, which can also make pregnant women have difficulty breathing, chest tightness and shortness of breath, which is manifested as an increase in heart rate of 10-15 times/minute even at rest; 3, respiratory speed: after pregnancy, the uterus will make the diaphragm position elevated, the amplitude of activity is reduced, the number of breaths and breathing depth The number of breaths and the depth of breathing will increase, so you will feel difficult to breathe and short of breath; 4, estrogen influence: estrogen will thicken the mucous membrane of the upper respiratory tract, appearing mild congestion and edema, at this time, pregnant women will show difficulty in breathing and shortness of breath, and more likely to occur in the upper respiratory tract infection; 5, other reasons: in addition to the above factors, with the increase in the size of the fetus in the uterus, there will be compression symptoms, difficulty in breathing and shortness of breath. It may also be because the pregnant woman is in a relatively small, confined space at this time, when entering a relatively large and well ventilated space, the performance of dyspnea, chest tightness and shortness of breath can be improved. Second, the pathological reasons 1, gestational hypertensive disease: pregnant women with gestational hypertensive disease due to vasospasm, blood pressure increases, so that the peripheral resistance of the heart increases, so it is easy to myocardial ischemia, interstitial edema, in serious cases may lead to heart failure, dyspnea, chest tightness and shortness of breath and other symptoms; 2, pregnancy combined with heart disease: after pregnancy, the heart burden increases, easier to appear myocardial systolic dysfunction and It usually occurs from late pregnancy to postpartum, mainly manifested as dyspnea, panic, cough, chest tightness and shortness of breath. If symptoms of dyspnea and shortness of breath occur after pregnancy, you need to take proper rest. If the symptoms are still not relieved after rest, you should go to the hospital in time to identify the cause and then carry out targeted treatment.