Approximately 23% of pregnant women with asthma experience an exacerbation or recurrence of symptoms during pregnancy, which is referred to as “pregnancy asthma”. During pregnancy, with the enlargement of the uterus and the elevation of the transverse septum, the transverse diameter of the thorax increases, which decreases the expiratory reserve and functional residual air volume and increases the tidal volume, which can also increase oxygen consumption, but because the septal mobility and chest wall muscles are not affected, this mechanical factor does not aggravate the asthma attack yet, but aggravates the hypoxemia during the asthma attack. In particular, the increase of prostaglandin F in pregnant women’s body, and prostaglandin F2a has a powerful effect on airway smooth muscle, and asthma patients are more sensitive to prostaglandin F2a, which can easily cause asthma attacks. After pregnancy, women with asthma must take active and appropriate measures to prevent and control asthma attacks, which can be done as follows: Prevention: After pregnancy, women with asthma should avoid asthma-promoting factors, such as pollen, dust, soot, spices, cold air and pets, prohibit smoking and avoid passive smoking, avoid mental stress and prevent respiratory infections. Actively treat “underlying” diseases. Mattresses and pillows should be covered with airtight covers, bed covers should be washed weekly with water at 60°C, and indoor humidity should be kept below 50%. Wear a mask when vacuuming. In addition, avoid going out at noon during the season when the concentration of allergens in the air increases. Pregnant women with asthma who have been inhaling glucocorticosteroids for a long time should not stop the medication abruptly because no specific effects of inhaled glucocorticosteroids have been found for pregnant women and fetuses. Patients with mild or moderate asthma who are known to be pregnant or preparing to become pregnant can switch to inhaled sodium cromoglycate, which has no teratogenic effect and no adverse effect on pregnant women, and is the preferred preventive medicine for pregnancy-related asthma. Observation: Both pregnant women with asthma and fetuses need to be observed for changes in their condition with appropriate screening methods. This is because maximum expiratory flow rate can indirectly estimate airway hyperresponsiveness and airway allergic inflammation, not only that, it can also be used as one of the objective bases for differential diagnosis when pregnant women have chest tightness and shortness of breath, so as to detect fetal hypoxia at an early stage. This indicates that the fetus has insufficient oxygen supply and is potentially at risk, which requires immediate and reasonable treatment. In addition, the fetus should be monitored regularly. In addition to observing fetal heartbeat and fetal movement, electronic fetal heart monitoring should be performed if necessary. Drug treatment: Appropriate drugs should be selected according to the degree of national severity of asthma attacks in pregnant women. In recent years, foreign scholars have confirmed through long-term animal experiments and clinical observation, especially through pharmacokinetic studies, that hydrocortisone, prednisone and prednisolone do not have much effect on the fetus, while dexamethasone enters the placenta at a greater concentration and has similar effects on the fetus and on the pregnant woman. According to the above results, if a pregnant woman with asthma needs to apply oral prednisone, prednisolone or IV hydrocortisone due to her condition, it is still safe for the pregnant woman and the fetus, but dexamethasone should not be used. Systemic glucocorticoid use should also be avoided during the first trimester of pregnancy. In some glucocorticoid-dependent asthma, systemic medications should be switched to inhaled medications as much as possible, with beclomethasone propionate being preferred. For such patients, the delivery process is critical and appropriate amounts of glucocorticoids should be given upon entry into the delivery room to prevent a decline in body glucocorticoids and asthma attacks due to physiological stress during delivery. For non-glucocorticoid-dependent pregnancy asthma, glucocorticoids should be used sparingly or not at all. The extent to which an asthma attack affects the pregnant woman and the fetus depends critically on the ability to control the asthma attack effectively. Most of the drugs currently used to control asthma have no significant side effects on the pregnant woman or the fetus. Pregnant women with well-treated and controlled asthma attacks generally do not suffer from miscarriage, preterm labor, obstructed labor, or obstructed labor during the entire pregnancy, and most of them can safely pass through the entire pregnancy and deliver normally. Mild asthma attacks have little effect on the fetus, and the birth score and birth weight of newborns are not significantly different from those of newborns born to normal mothers. If asthma remains uncontrolled for a longer period of time, the mother may experience pre-eclampsia, gestational hypertension, gestational toxemia, severe vomiting, vaginal bleeding, and obstructed labor. Fetal growth retardation in the uterus, overdue delivery, and low birth weight can occur. In case of severe asthma attacks, it can cause severe oxygen deprivation and functional disorders in pregnant women and fetuses, resulting in the birth of newborns with reduced weight or abnormal nervous system, and in some cases even threatening the lives of pregnant women and fetuses, and the perinatal mortality rate is two times higher than that of normal deliveries.