Pregnancy · Nutrition
Pregnancy Water Intake
6-8 glasses (~1.5-2 L) fluid daily NHS. Breastfeeding adds ~500-700 ml. Supports blood volume, amniotic fluid, prevents UTI + constipation. NHS / NICE.
Last reviewed 2 June 2026
Daily water intake
How much water do I need in pregnancy?
Activity level
Enter your pre-pregnancy weight to see your daily water target.
How much water
- NHS: 6-8 glasses (1.5-2 L) fluid daily.
- Pregnancy: ~300 ml extra T2 + T3.
- Breastfeeding: add 500-700 ml.
- Hot weather / exercise: more.
Why hydration matters
- Blood volume expansion 40-50%.
- Amniotic fluid production.
- Placental function.
- Prevent UTI.
- Reduce constipation.
- Reduce oedema (paradox — water helps).
- Thermoregulation.
Signs of dehydration
- Dark yellow urine.
- Dry mouth.
- Dizziness / lightheadedness.
- Headache.
- Fatigue.
- Constipation.
- Reduced urine output.
- Braxton Hicks more frequent.
Severe: tachycardia, low BP, sunken eyes, lethargy — medical attention.
Overhydration possible
Rare. Drinking very large amounts very fast can cause hyponatraemia (headache, nausea, confusion). Aim ~2-2.5 L/day max normal pregnancy.
During hyperemesis
- Small frequent sips.
- Ice chips / lollies.
- Electrolyte drinks.
- Avoid large volume at once.
- IV fluids if severe (maternity day unit).
Caffeine limits
- Max 200mg/day.
- Instant coffee: ~100mg.
- Brewed coffee: ~140mg.
- Tea: ~75mg.
- Energy drinks: avoid.
Hydration options
- Water.
- Milk.
- Herbal teas (pregnancy-safe).
- Fresh fruit in water.
- Dilute squash.
- Coconut water.
- Decaf coffee / tea.
Herbal teas
Safe: peppermint, ginger, rooibos, chamomile (occasional).
Avoid: large licorice, sage, parsley, blue / black cohosh.
UTI prevention
- Drink regularly.
- Urinate after sex.
- Wipe front-to-back.
- Avoid bubble baths.
Symptoms: dysuria, frequency, cloudy urine — GP urgent (prevent pyelonephritis).
Breastfeeding hydration
- Drink to thirst.
- Water beside you at every feed.
- Add ~500-700 ml over pre-pregnancy.
- Urine pale = adequate.
- Caffeine moderate.
Constipation
- Water 1.5-2 L+.
- Fibre (fruit, vegetables, whole grains).
- Gentle exercise.
- Fybogel / Movicol if needed.
- Iron supplements often worsen — GP review.
Different scenarios
Scenario 1: 22 wk, dark urine + headache
Dehydration likely. Increase fluids. Persistent: GP.
Scenario 2: Hot summer day, 32 wk
+25-50% more fluid. Electrolytes if heavy sweat. Shade.
Scenario 3: Hyperemesis can’t tolerate fluids
Maternity day unit. IV fluids + antiemetics.
Scenario 4: Breastfeeding 3 weeks, constant thirst
Normal. Drink to thirst. Water beside you at every feed.
Scenario 5: GDM diagnosed, sugary drinks usual habit
Switch to water + sugar-free. Dietician input. Monitor glucose.
Care guidance
- 6-8 glasses daily.
- Urine pale = adequate.
- Breastfeeding adds 500-700 ml.
- Caffeine ≤200mg/day.
- UTI symptoms = urgent GP.
- Avoid risky herbal teas.
Sources
- NHS. Healthy eating in pregnancy — water.
- NICE NG201. Antenatal care.
- RCOG. Hyperemesis gravidarum.
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Frequently asked questions
How much water do I need in pregnancy?
NHS guidance: ~6-8 glasses of fluid per day (~1.5-2 LITRES). Pregnancy adds: ~300 ml extra T2 + T3 vs pre-pregnancy. BREASTFEEDING: add 500-700 ml extra. SOURCES: water, milk, herbal teas (limit caffeinated), squash, juice (sugar limited), soups, water in food. AVOID excess caffeine (200mg/day) + alcohol entirely. /calculators/pregnancy-food-safety.
Why is hydration important in pregnancy?
(1) BLOOD VOLUME expansion (40-50% in pregnancy); (2) AMNIOTIC FLUID production; (3) PLACENTAL function; (4) PREVENT urinary tract infections (UTI common in pregnancy); (5) REDUCE constipation; (6) PREVENT preterm contractions (some link); (7) REDUCE oedema swelling (paradoxically water helps); (8) THERMOREGULATION.
Signs of dehydration?
(1) THIRST (late sign); (2) DARK YELLOW urine (should be pale); (3) DRY MOUTH; (4) DIZZINESS / lightheadedness; (5) HEADACHE; (6) FATIGUE; (7) CONSTIPATION; (8) REDUCED urine output; (9) BRAXTON HICKS more frequent; (10) NAUSEA worsening. SEVERE: tachycardia, low BP, sunken eyes, lethargy — medical attention.
Can I overhydrate?
RARELY but possible: water intoxication (HYPONATRAEMIA) from drinking very large volumes quickly. SYMPTOMS: headache, nausea, vomiting, confusion, seizures. AVOID: drinking very rapidly very large amounts. NORMAL pregnancy hydration aim ~2-2.5 litres/day max. SPORTSPEOPLE / heavy sweat: more. LISTEN TO body.
Hyperemesis — how to stay hydrated?
(1) SMALL FREQUENT sips; (2) ICE chips / ice lollies / frozen fruit; (3) ELECTROLYTE drinks; (4) AVOID large volume at once (worsens nausea); (5) PERSIST through nausea. SEVERE: IV fluids via maternity day unit. (6) DRY toast / crackers + sips together. /calculators/morning-sickness.
Caffeine intake limits?
MAX 200mg caffeine/day. Sources: instant coffee ~100mg/mug; brewed ~140mg; tea ~75mg; green tea 30-50mg; cola 40mg/330ml; chocolate 10-25mg/50g. ENERGY drinks contraindicated. EXCEEDING 200mg/day: linked to low birth weight + miscarriage.
Caffeine-free hydration options?
(1) WATER (still or sparkling); (2) MILK (calcium + protein bonus); (3) HERBAL teas (peppermint, ginger, rooibos — check pregnancy-safe; avoid sage, parsley, large licorice); (4) FRESH FRUIT in water; (5) DILUTE squash / cordial; (6) COCONUT water (electrolytes); (7) DECAF coffee / tea. AVOID: large licorice, fennel, blue cohosh.
Are all herbal teas safe?
NOT ALL. SAFE: peppermint (limit if reflux), ginger, rooibos, raspberry leaf (T3 only some advise), chamomile (occasionally), lemon balm. AVOID: large quantities of licorice (BP, preterm), fennel, parsley, sage, blue cohosh, black cohosh. NETTLE / dandelion: variable advice. CHECK with midwife if unsure.
Drinking water + UTI prevention?
Adequate hydration helps flush bacteria from urinary tract. UTI common in pregnancy (anatomy + hormones make susceptible). PREVENTION: (1) drink regularly; (2) urinate after sex; (3) wipe front-to-back; (4) avoid bubble baths / harsh soaps. SYMPTOMS: dysuria, frequency, cloudy / smelly urine, suprapubic pain, occasionally fever / haematuria. URGENT GP treatment to prevent pyelonephritis.
Breastfeeding hydration?
(1) DRINK to thirst — have water beside you at every feed; (2) URINE pale = adequate; (3) ADD ~500-700 ml extra over pre-pregnancy; (4) WATCH for headache, fatigue — could be dehydration; (5) ALCOHOL: avoid or moderate; (6) CAFFEINE: keep moderate; passes into milk in small amounts. MILK SUPPLY: dehydration can reduce; severe dehydration affects more.
Travel + hydration?
FLIGHTS, hot climates increase needs. (1) MORE FLUID +25-50% in heat; (2) AVOID large alcohol consumption; (3) ELECTROLYTE rehydration if heavy sweating; (4) PROTECT from heat with shade + cool clothing; (5) WATCH for heat exhaustion + cramps. PREGNANCY makes thermoregulation harder. PREPARE.
Constipation + water?
VERY COMMON pregnancy issue (progesterone slows gut). (1) WATER intake 1.5-2 L+; (2) FIBRE: fruit, vegetables, whole grains; (3) GENTLE exercise; (4) ESTABLISH routine; (5) BULK-FORMING laxatives (fybogel) if needed; (6) AVOID prolonged straining (haemorrhoids). PRENATAL iron supplements often worsen constipation — check with GP.
Pregnancy + diabetic / GDM hydration?
INSULIN-DEPENDENT or GDM: regular fluid important. WATCH: sugar-containing drinks can spike blood sugar (juice, sugary squash, sports drinks). USE: water, milk, sugar-free options. MONITOR for ketones (dehydration / inadequate carbs in GDM). DIETICIAN involvement helpful. /calculators/gestational-diabetes.
How does this relate to other calculators on BumpBites?
Companion: /calculators/calorie-calculator; /calculators/pregnancy-food-safety; /calculators/morning-sickness; /calculators/breastfeeding-calorie; /calculators/gestational-diabetes; /calculators/pregnancy-week.