The thickening of legs after pregnancy may be due to edema of both lower limbs, which occurs for the following reasons: 1. After pregnancy, the mother and the fetus need a lot of nutrients, especially the increased demand for protein, if it is not replenished in time, the plasma protein concentration in the body will decrease, as an important component to maintain the plasma osmotic pressure of pregnant women, once the plasma protein concentration is too low, it will make the water in the blood stream infiltrate into the tissue As the fetus grows, the uterus increases in size, and the uterine body compresses the surrounding tissues and organs, especially the inferior vena cava, resulting in venous reflux and obstruction of blood to the heart, resulting in swelling of the lower extremities. 3. Pregnant women usually do not pay attention to rest, are overworked, and are under too much psychological pressure, which can lead to edema of the lower extremities. However, as the causes of edema disappear at the end of delivery, the edema of both lower limbs will slowly subside and the legs will gradually change to normal.