Hello lybrate-user Mild swelling in feet at end of day can occur physiologically in pregnancy because of obstruction of blood vessel by enlarged womb. But if you find swelling even when you wake up in morning or if associated with pain-it is a warning sign that you should talk to your Obstetrician immediately. It can be indicative of clot in vein of your leg (Deep vein thrombosis) which require examination followed by doppler studies to confirm the diagnosis. Secondly swelling can also occur because of high blood pressure, which needs immediate evaluation.