How Much Water Should You Drink When Pregnant?

The National Academies’ guideline during pregnancy is about 10 cups (78 fl oz) a day from drinks, or 101 fl oz counting the water in food. ACOG, the American College of Obstetricians and Gynecologists, suggests 8 to 12 cups of water a day.

That’s the short answer. Here’s what it means in practice, why the number goes up, and what to watch for when you fall short.

How much water should a pregnant woman drink a day?

The National Academies set the Adequate Intake for pregnancy at 3.0 liters (about 101 fl oz) of total water a day. About 2.3 liters (78 fl oz, roughly 10 cups) of that is expected to come from drinks; the rest comes from food. For comparison, the figure for women who aren’t pregnant is about 74 fl oz (9 cups) from drinks, so pregnancy adds roughly a cup a day.

ACOG’s guidance lands in the same place: 8 to 12 cups (64 to 96 fl oz) of water a day.

Two things worth knowing about these numbers:

• They’re typical intakes, not minimums. Adequate Intakes describe what healthy people usually take in. Your own needs shift with body size, activity, heat and how you’re feeling, so treat 10 cups as a reference point, not a pass/fail line.
• Every drink counts. Milk, herbal tea, decaf and even caffeinated drinks all contribute. It doesn’t all have to be plain water.

You can see the pregnancy figure next to the ones for other women, in cups, on our women’s hydration statistics page.

Why “half your body weight in ounces” is a myth

You’ll often see pregnancy advice start from “drink half your body weight in ounces, then add more.” No study or health body sets water needs that way. The rule ignores the roughly 20% of water that comes from food, and it ignores activity, climate and health; the National Academies set intakes by age, sex and life stage, not weight. Our study of Google’s hydration answers found it repeated as fact on page-one results anyway. Some calculators (Hydrate’s included) do factor in your size, but treat any weight-based figure as a starting point, not a rule.

Why does pregnancy increase how much water you need?

Your body is doing a lot of extra work, and much of it runs on fluid:

Blood volume. Blood volume rises substantially during pregnancy to support the placenta and your baby, and more blood means more water to maintain it.

Amniotic fluid. Amniotic fluid is mostly water and is continually replenished. Your provider monitors its level; if it’s ever low, they’ll tell you what to do.

The placenta. The placenta moves nutrients and oxygen to your baby and carries waste away, and that exchange depends on your circulation.

Your kidneys. Your kidneys process more fluid during pregnancy, and many women find they pee more often, even early on.

Heat. Many women feel warmer and sweat more as pregnancy goes on, especially in the second and third trimesters and in hot weather.

Signs you’re not drinking enough while pregnant

Watch for:

• Dark yellow urine (pale straw is a good sign)
• Headaches
• Dizziness or lightheadedness, especially when standing up
• Fatigue beyond the usual pregnancy tiredness
• Dry mouth or dry skin
• Constipation getting worse

If you notice contractions or tightening that’s getting more frequent or stronger, don’t try to fix it with water alone: call your provider. Some women find Braxton Hicks ease after resting and drinking something, but your provider is the right person to judge what’s normal for you.

Can dehydration cause problems during pregnancy?

Being short on fluid can make some common pregnancy complaints worse:

Constipation. Pregnancy hormones slow digestion, and low fluid intake doesn’t help. Drinking enough, alongside fiber, is one of the simplest things to try first.

Urinary tract infections. UTIs are more common in pregnancy. Staying well hydrated means you pee more often, which is part of general advice for urinary health; it’s not a substitute for treatment if you have symptoms.

Feeling faint or unwell. Dizziness, headaches and fatigue are all harder to manage when you’re behind on fluids.

Serious dehydration, for example from repeated vomiting, needs medical attention. If you can’t keep fluids down, contact your provider.

How much water to drink in each trimester

The National Academies give one figure for the whole pregnancy, but how easy it is to reach changes a lot:

First trimester: Nausea and vomiting can make drinking hard. Small, frequent sips often work better than large amounts at once, and cold or iced water can be easier to keep down. Ginger tea, clear broths and coconut water all count. If you’re vomiting often, ask your provider about replacing electrolytes.

Second trimester: For many women the easiest stretch. The worst of the nausea has usually passed and the third-trimester discomfort hasn’t started, so it’s a good time to build a steady habit.

Third trimester: Pressure on your bladder means more bathroom trips, and it’s tempting to drink less to cut them down. Keep drinking anyway; spread it through the day and taper a little in the evening if night trips are wrecking your sleep.

Does it matter what you drink?

Water is the simplest choice, but these all count:

• Herbal teas (check with your provider: some herbs aren’t recommended in pregnancy)
• Milk (adds calcium and protein too)
• Coconut water (can be easier on a queasy stomach)
• Broth-based soups
• Diluted juice

Caffeinated drinks count toward your total too; the National Academies found they contribute to daily water intake like other drinks. The limit in pregnancy is about the caffeine itself, not hydration: ACOG advises under 200 mg of caffeine a day, roughly one 12-oz cup of brewed coffee, though cups vary a lot.

Avoid alcohol entirely during pregnancy.

Practical tips for hitting your goal

• Keep water within arm’s reach: on your nightstand, at your desk, next to the couch
• Use a large bottle (32 oz) so you can track progress without counting cups; two and a half refills gets you to about 78 oz
• Set reminders, since fatigue makes it easy to forget
• If plain water is unappealing (common in the first trimester), add cucumber, lemon or mint
• Eat water-rich foods such as cucumber, watermelon, strawberries and celery, which are mostly water and count toward the food side of your total

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Hydrate adjusts your daily water goal for pregnancy, so your target reflects your stage and your day, not a generic number. Join the waitlist.