Does the Time You Pump Affect Your Breastmilk? Does It Matter?

Does the Time You Pump Affect Your Breastmilk? Does It Matter?

Recent headlines made a big deal about the time of day breastmilk is pumped. But does the time you pump really matter? Our expert tells all.

Updated June 25, 2021

by Meg Nagle


Whether we like it or not, pumping breastmilk is something that millions of us end up doing at some point or another. The dreaded humming of the machine, sitting there feeling like a cow hooked up on the farm! It’s one of those “Why didn’t anyone tell me about this?” moments that we so often experience during the early months and years of motherhood. Pumping breastmilk can be frustrating. However, the benefits that you and your child will receive are immeasurable. By pumping, your baby continues to get all of the important components in your milk, and it keeps up your supply when you are separated from your baby.

One amazing thing about breastmilk is that your milk actually changes within each 24 hour period! The levels of various components change depending on the time of day (or night). So what does this mean? Is it OK to feed our baby pumped milk at 8:30 am that was expressed at 9:00 pm the night before?

Does the time you pump matter?

Recently, headlines began “informing” mothers that they should feed their baby expressed milk that was pumped at around that same time of day. People around the world started to message me in a panic! They were worried that if they didn’t feed their baby milk that was pumped at the same time, it would not be beneficial or “as good.” They worried that their baby wouldn’t sleep as well if the time didn’t match. Some articles even went as far as to say that it is a “mistake” if a baby is offered milk that was expressed at a different time than when it’s being offered. I am here to reassure you that it is perfectly okay to feed your baby milk that was pumped at a different time of day. It’s also important to consider the alternative if you’re not offering your baby your expressed milk.

When we look at the “best” practice of offering expressed milk, we also have to look at the alternative. It might not be possible for you to express enough milk at a certain time to be able to offer that milk at the same time on another day. If you have heaps of milk to offer your baby at 8:00 am that was expressed at 6:00 pm the day before, are you going to withhold that milk because it wasn’t expressed at the same time? No! Of course not! Your baby receiving milk at a different time of day will be far superior to offering formula milk that is the exact same every feed, 24/7. So why all of the hoopla around this topic?

Breastmilk does change to fit your baby’s needs.

There is no doubt that breastmilk changes within the feed itself, within a 24 hour period, and over the weeks, months, and years a child breastfeeds (Ballard & Morrow, 2013). We know that breastmilk over the nighttime hours actually contains components that can help a baby sleep (Sánchez et al., 2013). Even research shows how milk changes in zinc, calcium, and magnesium levels during a 24 hour period (Karra & Kirksey, 1988).

Breastmilk is an ever-changing liquid, which has been referred to as a living tissue or “white blood” (Wambach & Spencer, 2019) because of how incredibly adaptive it is. Breastmilk changes to meet your child’s needs the entire time they breastfeed for. From minute to minute, hour to hour, day to day. Would it be the best possible scenario to only feed directly from the breast 24/7? Yes! However, there is no doubt that the next best thing is expressed milk from the baby’s mother, regardless of the time it was pumped. This is because you are still touching your baby, exchanging germs. Your baby’s saliva interacts with your breastmilk, which then changes your milk’s composition that your baby needs (Sweeney et al., 2018). This exchange of germs is what makes the whole process so incredible. Over each day and night, your baby will get what they need.

Don’t panic! Fed is best.

Bottom line? Don’t stress. If you happen to be able to offer an expressed milk packet that was expressed around the same time it was given, great! But really, the most important part is that your baby is getting your milk. No matter the time of day or night. Breastfeed them as much as you can and seek help from an IBCLC if you are struggling. The sooner you can get help with pumping or any breastfeeding challenges, the better chance you’ll have of reaching your goals.

Ballard, O., & Morrow, A. L. (2013). Human Milk Composition. Pediatric Clinics of North America, 60(1), 49–74.
Karra, M. V., & Kirksey, A. (1988). Variation in Zinc, Calcium, and Magnesium Concentrations of Human Milk within a 24-Hour Period from 1 to 6 Months of Lactation. Journal of Pediatric Gastroenterology and Nutrition, 7(1), 100–106.
Sánchez, C. L., Cubero, J., Sánchez, J., Franco, L., Rodríguez, A. B., Rivero, M., & Barriga, C. (2013). Evolution of the circadian profile of human milk amino acids during breastfeeding. Journal of Applied Biomedicine, 11(2), 59–70.
Sweeney, E. L., Al-Shehri, S. S., Cowley, D. M., Liley, H. G., Bansal, N., Charles, B. G., Shaw, P. N., Duley, J. A., & Knox, C. L. (2018). The effect of breastmilk and saliva combinations on the in vitro growth of oral pathogenic and commensal microorganisms. Scientific Reports, 8(1).
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Meg Nagle RN, IBCLC
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Meg is the mother of three breastfed boys and lives with her husband and children in QLD, Australia. She is a Registered Nurse and an International Board Certified Lactation Consultant… Read more

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