There are three common causes of swollen feet in pregnant women, all related to pregnancy: firstly, generalised oedema symptoms caused by gestational hypertension syndrome, secondly, perinatal cardiomyopathy occurring in menstruating mothers over 30 years of age, and thirdly, oedema due to compression of the pelvic veins by the uterus, without clinical manifestations of proteinuria and rising blood pressure, and the swollen feet can subside on their own after delivery is complete.