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The importance of drinking water during pregnancy

For many women, pregnancy and lactation are very special life stages for taking care of their health and diet, in order to ensure the best start in life for their baby. However, even though changes in hydration physiology and balance are numerous during pregnancy and lactation, this topic is often overlooked. This document aims at providing an overview of the existing science on changes in hydration physiology, water balance and needs during pregnancy and lactation. Indeed, during pregnancy, changes arise in water dynamics.

These changes result in increased body water content and subsequent adaptations in its regulation. Preliminary evidence suggests health benefits result from an appropriate hydration during pregnancy. After birth, breastfeeding should be preferred whenever possible, as the ideal way to ensure the required nourishment for the newborn. However, lactation induces extra water loss for the mother. Considering the increased water needs during pregnancy and lactation, specific recommendations on fluid intake have been issued for these physiological stages.

Water makes up for a majority of our body weight. About 60 percent of our body is made up of water. It flushes out toxins from the body, regulates body temperature and helps in brain function, which makes it essential for our existence.
In the same way, the amount of water you consume during pregnancy is crucial as it carries nutrients to the baby, helps maintain the level of amniotic fluid, and prevents other pregnancy-related symptoms like constipation. For the same reason, it is important to drink plenty of water when you are expecting.

Why drinking water is important

A good intake of water will keep all your internal systems running well and helps your body remove waste. Waste in the kidneys dissolves in water and is flushed out via urine. This lowers your chance of urinary tract, bladder, and kidney infections.

The same goes for solid waste: Water softens the stool and makes bowel movements easier. If you’re like most pregnant women, you’ve probably experienced some constipation as a result of the hormonal changes in your body. Keep drinking and you’ll be less likely to develop another common pregnancy ailment: hemorrhoids.

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The measure of water drinking

In general, every person should drink 2 liters or 8–10 glasses of water daily to stay fit. This also includes juices and food from your diet that contain water like fruits, vegetables, and soups. Until about 27 weeks, you should have the same amount of water. Then with the growth of your baby, you should increase your fluid intake by about 500 ml.

But this is not the same for all. If you are overweight or you are overeating then you should consume more water. Dehydration during pregnancy will not only affect you but will also be harmful to your baby. Not drinking enough water can make you feel tired and constipated.


Signs of dehydration

Dehydration happens when you lose more fluid than you take in. Your body will signal that it doesn’t have enough water to carry on as usual. Here are the signs you should look out for:

  • Thirst and hunger: If you’re dehydrated, you may feel thirsty, hungry, or both.
  • Changes in urine: When you’re sufficiently hydrated, your urine is a pale-yellow color. Meanwhile, dark urine signals dehydration. If you’re pregnant and sufficiently hydrated, you may feel that you’ve taken up permanent residence in the bathroom.
  • Fatigue, dizziness, and headaches: Pregnancy is hard work, so it’s not surprising that you’re feeling tired a lot of the time, especially in those first months. Dehydration can cause both fatigue and headaches, so keep drinking to conserve the energy you do have.
  • Brain fog: There’s a name for that foggy brain that comes with pregnancy: Momnesia. But while momnesia is part of the deal, you don’t want to make it worse by not drinking enough. Your brain is powered, in part, by water. Being dehydrated by just 2% impairs your ability to carry out cognitive tasks Trusted Source.
  • Dry skin: Pregnant bellies are already itchy at times. Keep yourself hydrated so dry skin isn’t another reason for discomfort.


Sometimes even if you are drinking enough water you may be dehydrated and you need to increase your fluid intake. To know if you are drinking enough, check your urine. If your urine is dark yellow then increase your fluid intake. Apart from this, if you are feeling constipated, tired or feeling thirst tries to drink more liquid.


The body of a pregnant or breastfeeding woman undergoes specific physiological adaptations, to address the needs of the growing fetus or infant. These adaptations involve important changes in water physiology. During pregnancy, body water content increases, in particular due to larger plasma volume and amniotic fluid accretion within the mother’s body. Physiological adaptations occur in order to maintain water balance and homeostasis.

Fluid intake needs are also increased, and first evidence suggests that maintaining proper hydration might be important for fetal well-being, and, as for non-pregnant women, for preventing constipation and urinary tract infections recurrence. Breastfeeding women have even higher water requirements, in order to compensate for the water lost through breast milk. This loss can put water balance at risk, as the quantity of milk produced meets infant needs, even in the event of low fluid intake or dehydration of the mother. Recommendations are based on estimations of additional needs. Further research is needed to confirm changes of hydration status in pregnant women and the risk of dehydration in breastfeeding women.


Further reading

Anderson AS. Constipation during pregnancy: incidence and methods used in its treatment in a group of Cambridgeshire women. Health Visitor 1984.

Barker G, Boyd RD, D’Souza SW, Donnai P, Fox H, Sibley CP. Placental water content and distribution. Placenta 1994 Jan; 15(1):47-56. Beall MH, van den Wijngaard JPHM, van Gemert MJC, Ross MG. Amniotic Fluid Water Dynamics. Placenta.

Beetz R. Mild dehydration: a risk factor of urinary tract infection? Eur J Clin Nutr. 2003.

Benelam B, Wyness L. Hydration and health: a review. Nutr Bull. 2010; 35(1).

Bentley GR. Hydration as a limiting factor in lactation. Am J Hum Biol.

Borges VT, Rososchansky J, Abbade JF, Dias A, Peraçoli JC, Rudge MV. Effect of maternal hydration on the increase of amniotic fluid index. Braz J Med Biol Res. 2011.

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