Most of them are physiological factors, but the possibility of pathological factors cannot be ruled out, so the causes should be clarified and treated accordingly. Common causes: 1. physiological factors: 1. compression of lower limb veins: during pregnancy, the pregnant woman’s uterus keeps getting bigger, which compresses the veins of lower limbs and leads to poor blood flow, resulting in edema; 2. secretion of hormones: the secretion of maternal aldosterone becomes more after pregnancy, aldosterone is a hormone that can regulate the water balance of the body, when aldosterone increases, the body’s absorption of sodium and water is enhanced, and the body becomes more water, which also It will lead to edema. Pathological factors: 1. Hypertension during pregnancy: hypertension will affect the normal blood circulation of the body, slowing down the blood circulation and causing a large amount of body fluid to be stored in the subcutaneous tissue, which can cause edema. This edema will gradually spread upward, reaching the calves, thighs and even the abdomen, and may cause plasma cavity effusion in severe cases; 2. Other: In addition, kidney diseases during pregnancy, autoimmune diseases and hypothyroidism during pregnancy can also cause edema, and the cause should be clarified and the original disease should be actively treated. If edema is caused by physiological factors, appropriate interventions can be taken to reduce edema, such as appropriate exercise to promote fluid circulation and appropriate massage to promote blood circulation, which can also reduce edema. If it is caused by pathological factors, the pregnant woman’s blood pressure should be monitored closely to determine the blood pressure, proteinuria and whether the edema is gradually aggravated, and if necessary, medications such as methyldopa, hydrazidiazide and minoxidil can be applied for treatment.