How often should you pump?

You are likely to have heard that pumping every three hours is enough to establish or maintain a milk supply which meets your baby's caloric needs. However, in order to understand the best way to pump, it helps to understand frequent flexible breastfeeding first. You can find out about frequent flexible breastfeeding here, here, and here. The same principles apply to milk removal when you're doing it mechanically.

• There's little value in pumping for long periods of time e.g. more than 15 minutes with pump on both breasts (unless your milk happens to be flowing well and it's easy for you to continue).

• Short but frequent pumps work best (which mimic frequent flexible breastfeeding). Pumping irregularly, just when you have the energy, can be fine, too. It is better to pump for ten or even five minutes both breasts more frequently over the day, than to sit down and pump for half an hour or more, less often.

Pumping patterns which help or don't help

Multiple different strategies might be commonly recommended to boost your supply using the pump. I don't typically recommend any of the following.

• You may be advised to pump either immediately after or half an hour after a direct breast feed but I recommend pumping whenever it suits you for short bursts of five or ten minutes each breast. The more frequently you do it, even if for short periods of time, the better – much the same as baby suckling.

• You might be advised to do 'power pumping', which you can find out about here. By power pumping, people might mean

  • A burst of half an hour pumping both breasts, continuously. But because 60% of milk volume is transferred in the first two letdowns, and the amount of milk transferred with each subsequent letdown getting less and less, it is more efficient to do frequent but shorter pumps.

  • Pumping for ten minutes on, ten minutes off over an hour or so in the evenings when the baby is down for the night, for a few nights, to boost supply. You could do this. But would it be easier to simply offer the breast more during the day and evening, before your baby goes down for the Big Sleep at night? The breastfeeds don't need to be for long. Maybe you have terrible nipple pain and this isn't possible, but once we've sorted out underlying problems, your baby is your best pump.

• You might be advised to do ‘cluster pumping' e.g. a five to ten minute burst of pumping intermittently over a few hours of time. Again, this does better mimic the usual stimulation and milk removal of direct breastfeeding. However, it also raises again the question: would your baby take the breast, instead?

Why you don't need to worry about using expressed breast milk which was pumped at a different time of day to the time you are feeding your baby

You might have heard it said that you need to avoid feeding your baby 'mistimed' expressed breast milk - that is, breast milk which has been pumped at a time of day different to the time of day you're now feeding it to your baby.

In recent years, there has been cascading discoveries about just how variable and dynamic the concentration of a range of neurohormones and immune factors are in human milk. Scientists have discovered that the concentrations of many different components of human milk are affected by the daily journey of our planet Earth around the Sun.

This is a marvellous finding, although not a surprise, because although we forget about it all the time, every aspect of the human body and human life is fundamentally dependent upon and shaped by the Sun, including our cardiovascular system and our immune system.

As a result of the discovery of variable concentration of factors in human milk in response to the Sun, some breastfeeding support professionals have jumped to the conclusion that the changing levels of these neurohormones and factors in your milk must be strong enough to alter your baby's circadian clock settings and to improve baby's sleep. This is why you might have been told that you need to label all your expressed breast milk with time of pumping, so that you give it to your baby at the same time of the day!

But this is very hard work, and there isn't evidence to suggest it will benefit your baby in any way.

The Sun definitely influences the concentrations of neurohormones in your milk. But this doesn't mean that those neurohormones are driving your baby's sleep or circadian clock settings. In fact, the fluctuating concentrations of neurohormones in response to circadian variation are unlikely to have any meaningful impact upon your baby. Instead, your baby's body clock responds directly to the Sun and the activity in the environment around him.

You can find out about your baby's body clock and settings here.

Selected resources

Does cortisol affect baby or toddler sleep, including through breast milk?

The science of melatonin. Part 3: can breast milk be 'mistimed'?

The science of melatonin. Part 2: the research

The science of melatonin. Part 1: infant sleep

Selected references

Gridneva Z, Warden AH, McEachran JL, Perrella SL, Lai CT, Geddes DT. Maternal and infant characteristics and pumping profiles of women that rpedominantly pump milk for their infants. nutrients. 2025;17:366.

Kent JC, Mitoulas LR, Cregan MD, Geddes DT, Larsson M, Doherty DA, et al. Importance of vacuum for breastmilk expression. Breastfeeding Medicine. 2008;3(1):11-19.

Rosenbaum K, McAlister B. An integrative review of exclusive breast milk expression. Journal of MIdwifery and Women's Health. 2024:doi:10.1111/jmwh.13713.