Two large veins return blood to the heart from your feet and legs. As your baby grows, the enlarging womb presses on those veins, notes Michigan based OB/GYN Donna Harrison. “The veins then can't carry away as much fluid from your lower legs, and so your legs and feet swell,” says Harrison.
To address the common problem of swelling, Harrison adds, lie on your left side, with your feet level or slightly elevated. This takes the pressure off those veins and allow them to drain the fluid from your legs.