Mixing breastmilk
What makes breastmilk pumped in the AM versus PM different?
Breastmilk is a dynamic fluid that changes throughout the day, and one of these changes are the concentrations of hormones. The big ones I am talking about right now: cortisol (the “stress” hormone meant to promote alertness) and melatonin (the “sleep” hormone meant to promote drowsiness and sleep)
Studies on breastmilk have found that cortisol and melatonin follow a 24 hour circadian rhythm, with CORTISOL concentrations HIGHEST in the morning, peaking around 6am and MELATONIN concentrations HIGHEST at night, peaking around 3am
What does this mean?
Based on these findings, researchers SUGGEST there may be an impact on baby if breastmilk is “mistimed” (all breastmilk is pooled together, or AM milk is fed in PM or vice versa)
It is thought that if breastmilk is mistimed, it may affect baby’s sleep/wake cycle.
Although researchers have suggested that “mistimed” milk may have an impact, and it does seem to be a reasonable suggestion, further studies need to be done
What should you do?
It is completely UP TO YOU whether or not you decide to keep your milk separate!!
If you’re not sure what to do and you are concerned about the impact on your baby, you can experiment! Keep the milk separate and feed AM in AM and PM and PM for a few days, then switch to combining or “mistiming” the milk and see if there is any difference in baby’s sleep/wake cycle!
Some people swear they notice a difference, and others notice no difference
Another thing to consider: the costs versus benefits
If you are already struggling with the amount of work that goes into breastfeeding and you don’t feel like you can add worrying about what time milk was pumped to your plate, you don’t have to. Ultimately it is up to you. If this is going to be the thing that puts you over the edge, then I don’t want you to worry about it (this is MY OPINION. It is your choice to make)
If you choose to mix your breastmilk, you still want to follow safe storage guidelines:
Freshly expressed/pumping milk is good
at room temperature (77 degrees F or colder) up to 4 hours
in the fridge (40 degrees F) for up to 4 days
Following these guidelines, you would want to be sure to label the milk you mix with the date/time the OLDEST milk in the mixture is pumped and make sure it is frozen or consumed within those 4 days! Ideally any extra milk would be frozen as soon as you know it will not be needed (sooner than 4 days).
When freezing mixed milk, the date written on the freezer bag should be the date the OLDEST milk was pumped
Watch my video on Instagram about mixing milk:
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