Unfortunately, pregnancy and constipation go hand-in-hand. And when you’re sweating in the summer heat, less fluid is in your intestines, which makes the problem even worse. The best way to prevent it: fiber and fluids. Watermelon is a fiber-rich, water-dense fruit -- and in season now! -- but pretty much any fresh fruit and vegetable (cucumbers, blueberries and salad greens are all great) will help you ward off constipation, as will fiber-rich whole grains. If you’re still having trouble, ask your doctor about fiber supplements or stool softeners.