Recommended Daily Fluid Intake for Lactating Women
Lactating women should consume approximately 91 ounces (2.7 liters) of total water per day, which is about 24 ounces (700 mL) more than non-lactating women. 1, 2
Evidence-Based Fluid Requirements
The European Food Safety Authority (EFSA) establishes that adequate water intake for non-lactating females is 2.0 L/day (approximately 68 ounces), and lactating women require an additional 700 mL/day (approximately 24 ounces), bringing the total to approximately 2.7 L/day (91 ounces). 1
The Institute of Medicine guidelines align with this recommendation, specifying 2.7 liters daily for lactating women. 2
Practical Considerations
Sources of Water Intake
Total water intake includes both beverages and food sources. Research demonstrates that water from solid foods contributes substantially to total intake (approximately 640 g/day), with beverages providing the remainder (approximately 2,220 g/day). 3
Food water content must be counted toward total intake. Studies show that one-third of successfully lactating women consumed less than theoretical recommendations when only counting beverages, but many met needs when food water was included. 3
Individual Variation
Actual intake varies widely among successfully breastfeeding women. Population-based data shows lactating women consume an average of 2,242 g/day (median 2,164 g/day), with substantial individual variation. 4
Meeting the 91-ounce target is not universally necessary for successful lactation. Research indicates many women successfully breastfeed while consuming less than recommended amounts, suggesting physiological needs vary. 3, 5
Important Clinical Caveats
The Evidence on "Extra Fluids"
Advising women to drink beyond their thirst does not improve milk production. A Cochrane review found no evidence that forcing extra fluids increases breast milk supply. 5
Women should drink to thirst rather than forcing excessive intake. The physiological basis for improvement beyond meeting basic hydration needs remains unclear. 5
Monitoring Adequacy
Adequate hydration can be assessed by maternal thirst, urine color (pale yellow), and frequency of urination (every 2-3 hours). 2
The 91-ounce recommendation serves as a population-level adequate intake, not an absolute requirement for every individual. Only 27% of lactating women in research studies met this threshold, yet many successfully breastfed. 6
Practical Recommendation Algorithm
For clinical practice, advise lactating women to:
Aim for approximately 90-100 ounces (2.7-3.0 liters) of total water daily from all sources (beverages plus food). 1, 2
Drink to thirst and keep water readily available during breastfeeding sessions. 5
Count water from foods (fruits, vegetables, soups) toward the total, not just beverages. 3
Avoid forcing fluids beyond comfort, as this does not enhance milk production. 5