Drink lots of water.
Your fluid needs increase during pregnancy, partly to keep pace with your burgeoning blood supply, most of which is water. Plain old H2O is your best bet for keeping up with the demand. Water also cools your body, moves nutrients and waste, prevents constipation, and provides a cushion for your baby. Drink at least eight 8-ounce cups of fluid a day; low-fat milk and juice count. A cup a day of coffee or other caffeinated beverages won't hurt the baby, says Copel, but it may dehydrate you. To find out whether you're getting adequate fluids, check your urine: If it's light yellow or clear, you're drinking enough; if it's dark yellow, drink more.
Also, because the kidneys excrete salt actively during pregnancy, be sure to include a moderate amount of iodized salt in your diet, says Copel. Not consuming enough salt during pregnancy may actually predispose you to high blood pressure, and a lack of iodine can cause a form of mental retardation called cretinism in your child.