Pregnant women should aim for 8 to 12 cups of water a day, according to the American College of Obstetricians and Gynecologists. That’s roughly 64 to 96 ounces. The range is wide because your needs depend on your body size, activity level, climate, and how far along you are in pregnancy.
Why Water Matters More During Pregnancy
Your body’s blood volume increases by nearly 50% during pregnancy, and water is the raw material for that expansion. It carries nutrients to your baby through the placenta, supports kidney function as they filter waste for two, and helps form the amniotic fluid that cushions and protects the fetus.
A Cochrane review of four trials found that women who increased their water intake significantly boosted amniotic fluid volume. The mechanism is straightforward: extra water passes through the placenta into the fetal compartment, directly increasing the fluid surrounding the baby. This matters most when amniotic fluid levels are low, a condition called oligohydramnios, but even women with normal fluid levels saw increases when they drank more.
How Needs Change Across Trimesters
Research suggests total recommended intake during pregnancy falls between roughly 2,200 and 3,000 mL daily (about 74 to 101 ounces), with the specific amount shifting as pregnancy progresses. Interestingly, studies tracking actual drinking behavior find that women tend to consume the most water during the second trimester and the least during the third, even though the third trimester places the greatest physical demands on the body.
Hydration during the second trimester appears especially important for fetal growth. One study found that for every 10 percentage point increase in time spent dehydrated during the second trimester, birth weight dropped meaningfully. Staying consistent with fluids during this period supports the rapid fetal development happening between weeks 14 and 27.
What Dehydration Looks and Feels Like
Thirst is a late signal. By the time you feel thirsty, your body is already running low. Earlier, more reliable signs include a dry mouth or dry lips, headaches, dizziness, and dark yellow or amber-colored urine. Pale, straw-colored urine generally means you’re well hydrated.
Dehydration during pregnancy can also cause constipation, because your body pulls water from the digestive tract when it doesn’t have enough elsewhere. Fatigue, lightheadedness, heart palpitations, and low blood pressure are all common when fluid levels drop too far. If you’re experiencing any combination of these, increasing your water intake is the simplest first step.
Dehydration and Preterm Contractions
One of the more serious risks of dehydration in pregnancy is uterine irritability. When fluid levels drop, the uterus can become sensitive and begin cramping or producing irregular contractions. These sometimes feel like Braxton Hicks contractions, the “practice” tightening many women experience in the second and third trimesters. But if dehydration goes uncorrected, these contractions can progress and, in some cases, trigger actual preterm labor. Many labor and delivery units will start by giving fluids to women who come in with early contractions, because rehydration alone often stops them.
Practical Ways to Hit Your Target
Drinking 8 to 12 cups across a full day is more manageable than it sounds if you spread it out. A few strategies that help:
- Drink on a schedule, not by thirst. Have a glass when you wake up, one with each meal, one between meals, and one before bed. That alone gets you to 7 or 8 cups without much effort.
- Keep a water bottle visible. You drink more when water is within arm’s reach. A marked bottle that shows ounce measurements can help you track progress.
- Count other fluids. Milk, herbal tea, broth, and fruit-infused water all contribute to your daily total. Fruits like watermelon and oranges add meaningful water content too.
- Adjust for activity and heat. If you’re exercising, spending time outdoors in warm weather, or dealing with morning sickness that causes vomiting, you need more than the baseline 8 cups.
Morning sickness deserves special attention. If nausea makes it hard to keep water down, try small, frequent sips rather than full glasses. Cold water or water with a squeeze of lemon is often easier to tolerate than room-temperature plain water. Popsicles and ice chips work too.
Can You Drink Too Much?
It’s rare, but drinking extremely large amounts of water in a short period can dilute sodium levels in your blood, a condition called hyponatremia. This is unlikely at normal intake levels. Staying within the 8 to 12 cup range and drinking steadily throughout the day rather than chugging large volumes at once keeps you in safe territory. If you’re ever unsure whether your intake is right, urine color remains the simplest gauge: pale yellow means you’re on track.