Y'know, I don't know if this be of any help at all, but...
When I was pregnant, my midwife told me to eat cucumbers, blueberries, spinach, and watermelon to prevent swelling. I had read so much pregnancy and birth literature at the time that I was researched out, and I never even asked why. I just figured that you couldn't really go wrong with spinach and blueberries, so I just blindly followed her advice. In the end, I made it all the way to the birth with all my shoes and my wedding rings still fitting.
There were a couple of times my feet and legs started to swell (when my parents would visit, and I my diet would be upset). But I would return to the cucumbers, spinach, watermelon, and blueberries....and the swelling would go away. I still have no idea why it worked, and I suppose it could have been a fluke coincidence. But hey, you can't go wrong with spinach and blueberries. My midwife had me eating one whole, small cucumber each day, and one spinach salad at lunch each day. It might be worth a try.