As the weather gets warmer and mothers and babies begin to spend more time outdoors breastfeeding mothers always wonder whether their babies need to be supplemented with water. The answer to this question is no! Breastmilk contains 88% water and breastmilk is perfected formulated to satisfy baby’s needs no matter what the weather is. Giving water to a breastfeeding baby 6 months and younger is actually more dangerous than helpful. A breastfeeding mother who herself is well-hydrated and is allowing her baby to breastfeed as often as the baby desires will stay perfectly hydrated no matter how hot the weather becomes. A number of studies have been done in various locations (both humid and dry) at temperatures ranging from 22-41°C (71.6-105.8°F) and 9-96% relative humidity and these studies have determined that an exclusively breastfed baby does not need extra water . Giving supplemental water to a newborn (under 5 weeks old) can actually be dangerous. Too much water can dilute the sodium in the baby’s bloodstream to the point where “oral water intoxication” develops. Oral water intoxication can lead to symptoms like low body temp, bloating, and seizures. Breastfeeding babies that have reached the 6 month mark also do not need water, but it is not harmful if they occasionally sip water from a cup.
Although breastfed babies do not need any supplemental water, it is interesting to note that formula fed babies sometimes do require some water. Formula fed babies may need water supplements due to the renal solute load of formula (the higher salt level is harder on their kidneys, and they may need extra water in order to excrete it). Formula fed babies also have less efficient metabolisms than breastfed babies, so they use up water faster.