Reviewed by The Mom Store editorial team, October 2026. See our editorial policy.
You need a little more fluid than usual while you are pregnant, and more again on hot days. The NHS guide to water, drinks and your health uses 6 to 8 cups or glasses of fluid a day as a general guide for adults, and says you may need more if you are pregnant or breastfeeding, in a hot environment, or active for long periods. There is no single number that suits everyone. A simpler check is the colour of your pee: the NHS suggests drinking enough during the day that it stays a pale colour.
Many lists online promise ten or more proven benefits of drinking water in pregnancy. The honest picture is shorter. Drinking enough keeps you from getting dehydrated, which in turn helps you avoid the headaches, dizziness and tiredness that dehydration causes. Claims that extra water prevents stretch marks or treats swelling or contractions are not backed by the health guidance linked here.
What counts
The NHS says water, lower fat milk and lower sugar drinks, including tea and coffee, all count towards your daily fluid. A few things to keep in mind in pregnancy:
- Caffeine. Chai and coffee count as fluid, but the NHS advises no more than 200mg of caffeine a day in pregnancy, because more than this could increase the risk of miscarriage or low birth weight. The NHS puts a cup of instant coffee at about 100mg and a cup of tea at about 75mg.
- Juice and sugary drinks. The NHS suggests keeping fruit juice and smoothies to a small 150ml glass a day with a meal, and not having high sugar drinks too often.
- Buttermilk, nimbu pani and coconut water. These are all fluids and can make it easier to drink more in summer. Watch the sugar and salt you add to nimbu pani or packaged versions.
Signs you are not drinking enough
The NHS page on dehydration lists the usual signs: feeling thirsty with a dry mouth and lips, a headache, feeling dizzy or light headed, tiredness, dark yellow and strong smelling pee, and peeing less often than usual. Vomiting, diarrhoea, a fever and long spells in the heat all raise your risk, so a bout of morning sickness or a stomach bug in summer is when to pay closest attention.
Habits that make it easier
- Keep a filled bottle where you spend most of your day, and another by the bed.
- Drink with every meal and snack rather than trying to catch up in the evening.
- If plain water is hard to face with nausea, try small sips often, cool water, or water with a slice of lemon or a few mint leaves.
- Drink before you go out in the heat, and carry water when you travel or walk.
- If you are waking at night to pee, drink more earlier in the day instead of cutting down overall.
Swelling is not a sign to drink less
Swollen ankles and feet are common in later pregnancy. The NHS advice on swollen ankles, feet and fingers in pregnancy is to avoid standing for long periods, wear comfortable shoes, rest with your feet up and keep moving with walks or foot exercises. Cutting back on water is not on that list.
When to get medical help
Contact your doctor or maternity unit urgently if you have:
- a sudden increase in swelling in your face, hands or feet, a very bad headache, blurred vision or flashing lights, or severe pain just below your ribs, which the NHS lists as possible signs of preeclampsia
- dizziness when you stand that does not go away, or you are peeing much less than normal, despite drinking
- vomiting that stops you keeping fluids down
Go to the emergency department straight away if you feel confused, very drowsy, have cold or blotchy skin, or are breathing fast and shallow. The NHS lists these as signs that dehydration may have become serious.
This article is general information and does not replace advice from your doctor.
