What are the risks of feeding a newborn refrigerated milk that has not warmed to room temperature?

From the Guidelines

Feeding a newborn refrigerated milk that hasn't warmed to room temperature poses a risk of causing discomfort and digestive issues, and it is recommended to warm the milk to room temperature or body temperature before feeding. The American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care in 2015 emphasizes the importance of maintaining normal temperature in newborns, as hypothermia is associated with serious morbidities such as increased respiratory issues, hypoglycemia, and late-onset sepsis 1. While the guidelines do not specifically address the temperature of milk for feeding, they do recommend maintaining the newborn's temperature between 36.5°C and 37.5°C after birth through admission and stabilization (Class I, LOE C-LD) 1.

Some key points to consider when feeding a newborn include:

• Cold milk can lead to stomach upset, increased gas, and potential digestive discomfort in newborns
• The sudden temperature change might also cause the baby to reject the feeding or consume less milk than needed
• Cold milk requires more energy for the baby to warm internally, potentially using calories that would otherwise support growth
• For premature or low birth weight infants, this energy expenditure is particularly concerning
• The ideal temperature for feeding is body temperature or room temperature

To warm refrigerated milk safely, it is recommended to:

• Place the bottle in a bowl of warm water for a few minutes
• Use a bottle warmer
• Test the temperature on your wrist before feeding
• Never microwave breast milk or formula as this creates dangerous hot spots. While not dangerous in most cases, warming milk provides a more comfortable feeding experience for your baby and supports optimal digestion and nutrition absorption.

From the Research

Risks of Feeding Newborn Refrigerated Milk

• There is a risk of bacterial growth in refrigerated milk that has not been warmed to room temperature, as bacteria can multiply rapidly at temperatures above 8 degrees C 2.
• However, studies have shown that refrigerated breast milk can be safely stored at 4-6 degrees C for 72 hours without significant bacterial growth 2.
• The risk of bacterial contamination is higher in unheated breast milk, with studies showing that unheated samples had a significantly higher number of samples positive for bacterial growth at each time point 3.
• Refrigeration of thawed milk can result in greater declines in pH and bacteria, and increases in free fatty acids, which may affect the integrity of the milk 4.
• Storage of human milk at 15 degrees C is safe for 24 hours, whereas at 25 degrees C it is safe for 4 hours, and milk should not be stored at 38 degrees C 5.

Bacterial Safety

• Flash-heating breast milk can eliminate bacteria and prevent growth over time, making it a safe option for storage at room temperature for up to 8 hours 3.
• Unheated breast milk samples showed growth of E. coli and S. aureus, while flash-heated samples showed no pathogenic growth 3.
• Bacterial growth is restricted mainly to non-pathogens at lower temperatures, but can be considerably higher at 38 degrees C even during short periods of storage 5.

Milk Integrity

• Thawing and warming breast milk can affect its integrity, with changes in pH, bacterial colony counts, and free fatty acids, but not adversely 4.
• The integrity of breast milk is affected similarly by different thawing and warming methods, with no differences in fat, protein, lactoferrin, and secretory IgA with processing steps 4.