Pregnant women should drink about 2.3 liters (roughly 10 cups) of fluid per day, which is approximately 300 milliliters more than the standard recommendation for non-pregnant women. That extra amount is roughly one additional glass of water daily, though individual needs vary based on activity level, climate, and how far along the pregnancy is.
Why Your Body Needs More Water During Pregnancy
Pregnancy dramatically increases your body’s demand for water. Your blood plasma volume expands by 40 to 50 percent to supply the placenta and support your growing baby. Your body also produces amniotic fluid, maintains a higher skin blood flow for temperature regulation, and supports the development of new tissue. All told, total body water increases by roughly 5 to 8 liters over the course of a full pregnancy.
That fluid doesn’t just sit in one place. It circulates to regulate blood pressure, deliver nutrients through the placenta, cushion the baby inside the amniotic sac, and help your kidneys filter a much larger volume of blood than usual. Without enough incoming water, your body has to make trade-offs, and some of those trade-offs carry real consequences.
How Needs Change Across Trimesters
Current guidelines treat pregnancy as a single stage when it comes to water intake, but researchers at Penn State University have pointed out that each trimester places different physiological demands on the body. Their work found that women typically become underhydrated during the second trimester and into the early part of the third trimester, a period when blood volume is expanding rapidly and amniotic fluid volume is climbing.
In the first trimester, nausea and vomiting can make it harder to keep fluids down, so sipping small amounts frequently tends to work better than drinking large quantities at once. By the second and third trimesters, your fluid needs are genuinely higher, but most women don’t adjust their intake to match. If you’re feeling more fatigued, lightheaded, or constipated than usual during these later months, inadequate hydration is one of the simplest explanations to rule out.
What Counts Toward Your Daily Intake
Plain water is the most straightforward choice, but it isn’t the only fluid that counts. Milk, herbal tea, broth, and water-rich fruits and vegetables all contribute to your daily total. Even foods like watermelon, cucumbers, oranges, and soups add meaningful amounts of fluid.
Water contains trace amounts of electrolytes, and for most pregnant women that’s enough to stay properly hydrated. Electrolytes like sodium and potassium help direct water to where your body needs it, which matters more during pregnancy because your fluid volume is so much higher. If you’re showing signs of dehydration (dark urine, dizziness, dry mouth), an oral rehydration solution or water with added electrolytes can be more effective than plain water alone, since it helps your body absorb and retain the fluid rather than just passing it through.
Caffeinated drinks do count toward fluid intake, though caffeine has a mild diuretic effect. Sticking to moderate caffeine levels (under 200 mg per day, or about one 12-ounce cup of coffee) is the standard guidance during pregnancy.
Risks of Not Drinking Enough
Dehydration during pregnancy isn’t just uncomfortable. Insufficient fluid intake has been linked to preterm birth, low amniotic fluid levels, and fetal malformations. A study of second-trimester women in China found a direct, moderate-strength correlation between total fluid intake and amniotic fluid index: women who drank more had measurably higher amniotic fluid levels.
Low amniotic fluid restricts the baby’s ability to move and increases pressure on the umbilical cord, which raises the risk of oxygen deprivation. These aren’t abstract clinical concerns. They translate into real complications that can affect delivery and the baby’s health.
Dehydration can also trigger Braxton Hicks contractions, the practice contractions that cause a tightening sensation in your uterus. These are most common in the third trimester but can start in the second. Frequent Braxton Hicks contractions are one of the clearest signals that you need more fluids. Many women find that drinking a full glass of water and lying down resolves them within 15 to 30 minutes.
Signs You’re Not Getting Enough
The easiest check is urine color. Pale yellow to nearly clear means you’re well hydrated. Dark yellow or amber means you need more. Other signs to watch for include:
- Dry or sticky mouth
- Headaches that come on in the afternoon
- Dizziness when standing up
- Constipation
- Frequent Braxton Hicks contractions
- Feeling unusually tired despite adequate sleep
Keep in mind that prenatal vitamins and certain supplements can change urine color on their own, so look at the overall pattern rather than any single bathroom trip.
Practical Tips for Staying Hydrated
Drinking 10 cups a day sounds manageable in theory, but pregnancy symptoms like nausea, heartburn, and a compressed bladder can make it harder than expected. A few strategies that help: carry a marked water bottle so you can track your intake visually, set a few phone reminders spread across the day, and front-load your drinking earlier so you’re not chugging water before bed (which just means more nighttime bathroom trips).
If plain water feels unappealing, especially during the first trimester when taste aversions are common, try adding slices of lemon, cucumber, or berries. Cold or ice water is often easier to drink when you’re nauseous. Popsicles made from fruit juice can also help on days when sipping feels like a chore.
Hot weather and exercise both increase your needs beyond the baseline 10 cups. If you’re active or live in a warm climate, aim higher and pay closer attention to urine color. Women carrying twins or triplets have similar baseline fluid guidance (about 10 cups), but should be especially attentive to hydration given the greater demands on blood volume and amniotic fluid production.
After Pregnancy: Breastfeeding Needs
If you plan to breastfeed, your fluid needs will stay elevated after delivery. Producing breast milk requires significant water, and most lactating women need even more than they did while pregnant. The general recommendation for breastfeeding is about 3.1 liters (13 cups) of fluid daily. Building strong hydration habits during pregnancy makes that transition easier.