Level 2 1: Why do pregnant women have swollen feet? Swollen feet are very common in pregnant women, especially in late pregnancy. This is because as the fetus grows, it gradually becomes larger, compressing the veins and lymphatic vessels, resulting in poor blood and lymph circulation, causing water retention and leg edema. In addition, the hormone levels of pregnant women will also change, causing blood vessels to dilate and blood flow to increase, which will also aggravate leg swelling.