Trimester-specific fluid goals, lactation water cost, and warning signs for dehydration during pregnancy.
Pregnancy increases blood volume by nearly 50% by the third trimester. That extra blood needs water. Breastfeeding requires an additional 700–1,000 mL per day because breast milk is 87% water.
This calculator adds the trimester-specific increase to your baseline: +300 mL in first trimester, +500 mL in second, +700–800 mL in third, and +700–1,000 mL while breastfeeding. The result is your total fluid from all sources — beverages and food.
Warning signs to watch for: Dark urine, dizziness, decreased fetal movement, or sudden swelling in hands/face. If you experience these, increase fluids and contact your provider.