How much water should I drink while pregnant?

The Institute of Medicine recommends pregnant women drink about 3.0 liters (10 cups) of total fluids daily. This is approximately 300ml more than non-pregnant women. Your specific needs depend on your weight, activity level, and trimester.

How much water should I drink while breastfeeding?

Breastfeeding mothers need an additional 700-1000ml of water daily beyond normal requirements to support milk production. Breast milk is about 87% water. A good rule is to drink a glass of water every time you nurse.

Can dehydration cause contractions?

Yes, dehydration is a common trigger for Braxton Hicks contractions (false labor). If you experience contractions, try drinking 2-3 glasses of water and resting. If contractions persist or become regular, contact your healthcare provider.

What drinks count toward hydration during pregnancy?

Water is best, but milk, 100% fruit juices (in moderation), and caffeine-free beverages also count. Limit caffeine to 200mg daily (about one 12oz coffee). Herbal teas should be checked with your provider as some herbs aren't recommended during pregnancy.

For Expecting & New Mothers

Pregnancy Hydration Calculator

Calculate your personalized water intake during pregnancy and breastfeeding, based on ACOG and IOM clinical guidelines.

Clinical Guidelines: Based on American College of Obstetricians and Gynecologists (ACOG) and Institute of Medicine (IOM) Dietary Reference Intakes for water during pregnancy and lactation.

Pre-pregnancy Weight

Your weight before pregnancy

Unit

Stage

Activity Level

Climate / Season

Experiencing morning sickness or nausea

Hydration During Pregnancy: What the Research Says

Scientific Methodology

This calculator is based on evidence-based guidelines from leading medical organizations:

1
Institute of Medicine (IOM) Dietary Reference Intakes
The IOM recommends pregnant women consume approximately 3.0 liters (about 10 cups) of total water daily, compared to 2.7 liters for non-pregnant women.
2
ACOG (American College of Obstetricians and Gynecologists)
ACOG emphasizes the importance of adequate hydration for maintaining amniotic fluid levels and supporting increased blood volume during pregnancy.
3
Lactation Research
Breastfeeding mothers need an additional 700-1000ml of water daily to support milk production, as breast milk is approximately 87% water.

Why Hydration Increases During Pregnancy

Stage	Body Changes	Additional Water Needed
First Trimester	Blood volume begins increasing; potential morning sickness	+200ml/day
Second Trimester	Blood volume up 45%; amniotic fluid production	+300ml/day
Third Trimester	Maximum blood volume; full amniotic fluid	+400ml/day
Breastfeeding	Milk production requires significant fluid	+700-1000ml/day

Signs of Dehydration During Pregnancy

Pregnant women should be alert to these dehydration symptoms:

Dark urine - Should be pale yellow
Maternal overheating - Feeling unusually hot
Braxton Hicks contractions - Dehydration can trigger false contractions
Dizziness or lightheadedness
Headaches
Dry lips and skin

Research Citations

Institute of Medicine (2004). “Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate.” National Academies Press.
ACOG Practice Bulletin No. 189 (2018). “Nausea and Vomiting of Pregnancy.” Obstetrics & Gynecology, 131(1), e15-e30.
Rosinger AY, et al. (2022). “Total water intake during pregnancy and lactation.” American Journal of Clinical Nutrition.
Bardosono S, et al. (2017). “Fluid intake of pregnant and breastfeeding women in Indonesia.” British Journal of Nutrition, 117(S1), S43-S51.

Medical Disclaimer

This calculator provides general guidance based on clinical recommendations. Every pregnancy is unique. Always consult with your healthcare provider about your specific hydration needs, especially if you have conditions like gestational diabetes, preeclampsia, or are carrying multiples.

Method & Scientific Basis

Baseline body-weight intake (33 ml/kg) plus a trimester adjustment (200 / 300 / 400 ml for first / second / third) reflecting blood-volume expansion and amniotic-fluid demands, plus mild activity and hot-climate adjustments. Morning-sickness adds 300 ml and breastfeeding adds 800 ml, derived from IOM and ACOG guidance.

References

Institute of Medicine — Dietary Reference Intakes for Water (2004) — Pregnancy water reference (3.0 L total/day) and breastfeeding addition (700–1000 ml).
ACOG — Practice Bulletin No. 189: Nausea and Vomiting of Pregnancy — Source of the morning-sickness fluid-replacement guidance.
Rosinger — Water intake during pregnancy and lactation (American Journal of Clinical Nutrition, 2022) — Trimester-specific intake patterns and lactation needs.
EFSA — Scientific Opinion on Dietary Reference Values for Water (2010) — European pregnancy/lactation water requirements (cross-check against IOM).

Important: Pregnancy hydration needs vary widely. Always verify these estimates with your obstetrician, particularly if you have hyperemesis, gestational diabetes, or pre-eclampsia.