It’s common practice to date breast milk before storing it. Do you also make a note of the time of day at which you pumped it, though? Because the composition of milk actually changes over the course of the day to facilitate Baby’s sleep cycle, breastfeeding moms should track the milk they store closely. If your baby hasn't been resting well, here’s what you should know about the impact your output may be having. 

How Breast Milk Changes Every 24 Hours

Generally speaking, babies should drink breast milk at the same time of day that's it’s expressed. If you’re breastfeeding your baby directly, you don’t even have to think about this. When it comes to storing milk, though, you should separate the milk that’s pumped during the day from the milk that’s pumped at night. 

Researchers have found that breast milk produced at nighttime contains higher levels of nucleotides. Nucleotides are essentially the building blocks of nucleic acids, and the ones present in breast milk—adenosine, guanosine, and uridine—promote restfulness and sleep. Scientists also found higher concentrations of melatonin in milk expressed later during the day. Known as the “sleep hormone,” melatonin helps regulate sleep cycles. 

breastfeedingHow to Give Baby the Right Milk

Once you get into a good routine, giving your baby milk with the right composition will be second nature. Simply timestamp all the milk you store, and separate it in the freezer. 

It’s also important to maintain your own sleep schedule. Obviously, this is easier said than done when caring for a newborn or young baby. Your milk composition responds to your own circadian rhythm, though, so if you’re not sleeping well, your milk may not contain all the nucleotides it needs to help your little one rest. 


For more tips on breastfeeding, turn to the friendly lactation team at Geneva Woods Birth Center. Serving women throughout Anchorage, AK, and the surrounding areas, this OB-GYN practice provides comprehensive prenatal and postpartum care. Their certified nurse-midwives and IBCLC’s use evidence-based techniques and always give individualized care to their clients. To learn more about the support they offer, visit their website or call (907) 561-2626 with questions.