Answer: During pregnancy, your body produces about 50 percent more blood and other body fluids to help baby grow. (In fact, about 25 percent of your pregnancy weight gain is from fluid retention—take that, double cheeseburger and fries!) And some of that extra fluid is going to fill up your tissues, especially in your hands, feet, legs and ankles. What do all these fluids do? They help soften your body, allowing your joints and tissues to open up and prepare for delivery. You’ll typically see more swelling around your fifth month, lasting through the third trimester.