Hydration for pregnant and breast feeding women

Because of the particular importance and responsibility of the pregnancy and lactation phases, it is often a time when mothers modify their nutritional habits and lifestyles to ensure the best and healthiest start in life for their new child.
Most pregnant and lactating women are likely to pay attention to living healthily and eating healthily– it is important that health care practitioners should ensure that hydration is not overlooked.

Indeed, weight increases about 12 kg during pregnancy, and most of this added weight, 6 to 9 L, is water1, because:

  • The plasma volume (which is mainly water) increases
  • 85% of the placenta is water2
  • The fetus itself is 70-90% of water

To ensure adequate water intakes during pregnancy, the EFSA recommends an increase of 300 mL per day compared to the normal intake for non-pregnant women, taking total adequate water intake (from food and fluids) to 2,300 mL, or approximately 1,850 mL/ day from fluids.3

During lactation, water intake needs to compensate for the loss of water through milk production. Milk is made of 88% water, and the EFSA therefore recommends that lactating women increase their water by about 700 mL/day, meaning an adequate intake of 2,700 mL/day (from food and drink), or approximately 2,200 mL/day from fluids.



  1. Institute of Medicine (IOM). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: National Academies Press,2004.
  2. Beall MH, van den Wijngaard JPHM, van Gemert MJC, Ross MG. Amniotic Fluid Water Dynamics. Placenta 2007;28:816-23.
  3. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary reference values for water. EFSA Journal 2010; 8:1459-1507. doi:10.2903/j.efsa.2010.1459. Available online: www.efsa.europa.eu

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