Aim for eight 8-ounce glasses per day (64 fluid ounces) of fluid, plus one 8-ounce cup for each hour of light activity. Milk, juice, decaffeinated drinks, and caffeinated drinks all contain plenty of water and “count” toward your fluid intake.
Keep in mind that juice and sweetened drinks also provide a lot of extra calories, so don’t rely on them too much.
It’s best to limit caffeine, too – including caffeinated teas and colas – to 200 mg (about one 12-ounce cup) per day. More than that raises the risk of miscarriage, according to a 2008 study.
(It’s a myth that caffeinated drinks dehydrate you. Yes, caffeine makes you pee more. But the amount of fluid you actually lose because of this diuretic effect is so small that it’s insignificant.)
Don’t hesitate to drink water and other fluids because you’re afraid of retaining water, either. Oddly enough, the more fluids you drink during pregnancy, the less your body retains. So if your feet and ankles are swollen, drinking more water actually helps.
Water carries nutrients through your blood to your baby, and drinking plenty of fluids helps prevent dehydration, too. This is especially important in the last trimester, when dehydration can cause contractions that can trigger preterm labor.
Water also helps prevent some common pregnancy problems such as constipation, hemorrhoids, and bladder infections (drinking water helps dilute your urine, which reduces your risk of infection).
If you need to drink more fluids, you don’t want extra calories, and you don’t like the taste of water, try adding a wedge of lemon or lime to your water, or a little juice, for additional flavor. If you’re not sure how much water you drink each day, fill a container with your target amount and try to finish it by the end of the day.