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We are increasingly being asked what the main differences are between the NurtureGoods Smart 1.0, 2.0 and 3.0 in terms of suction power and pumping frequency. We have put together an article especially for everyone who wants to know the difference more clearly.

Please note! It is important that every mother finds the most comfortable suction for her for the best result during pumping.

What does suction and frequency mean on a breast pump?

To explain important things like the suction power of breast pumps, we will first take you through a few terms like mmhg and CPM (Cycles per minute). When you buy a breast pump you might see mmhg on the packaging or product listing. The force of suction on breast pumps is measured as mmhg. This stands for the English term "millimeters of mercury" and is the standard unit of vacuum pressure. Breast pumps are measured with negative mmhg (pressure) and falls on average in a range of 200 to 350 mmhg, which is the maximum suction power of the breast pump. CPM or Cycles per minute is a measure of how often the breast pump sucks in a given time (1 minute). The cycles range of the most famous models on the market varies from 20 to 80 cycles per minute and often depends on the suction power with which the pump pumps breast milk.

There have been several studies done on infant suction and frequency. One study indicates that the average suction of an infant is between 45 and 55 cycles per minute. And that good breast pumps should comply with this. The Swedish Engineer Einar Egnellinventor of the industry standards for mmhg and CPM, claims that a healthy natural cycle per minute is between 30-60 cpm and that suction is between 220 and 230 mmhg. This is also one of the reasons why all NurtureGoods breast pumps are capable of reaching a minimum of 250 mmhg to meet the unique needs of mothers and their babies. (Egnell E. et al, in a 1956 study)

How hard should a breast pump be able to suck and with what frequency?
Egnell has determined that 220 mmhg is the safest maximum for automatic breast pumps. However, there are other studies that show that there are mothers who suffer from sensitive breasts and nipples at lower suction forces. Therefore, it is important for each mother to find the most comfortable suction for her. Hartman's research in 2008 has shown that this leads to a higher milk yield. The following figure shows the required force per mother (Hartman et al., in a 2008 study)

This image is related to Hartman's research The Importance of Vacuum for Milk Expression Breastfeeding Med 3(1) (2008) and presented at the Amarillo Conference in 2009.

What should you look for in a breast pump?
Vacuum, cycles per minute and suction power play a central role in efficient pumping. They are the three critical technical success factors that ensure that you can pump properly. Professional medical pumps are bound by certification DIN EN ISO 10079 and may not exceed 248 mmhg. This means that the vacuum suction in expression mode should be between 23 and 248 mmhg. For stimulation mode this should be between 38 and 195 mmhg. In comparison, most babies suck with an average force of 150 to 220 mmhg. A good breast pump should be able to achieve this. (Lawrence & Lawrence, 1999).

Lawrence's research also reported that a baby's sucking rhythm in the stimulation phase of breast pumping is between 70-120 cycles per minute. Once the milk starts to flow the rhythm changes to 30-60 cycles per minute, which the original research by Einar Egnell in 1956 has already confirmed. Only 3 to 5% of total milk production is removed when pumping before the first let-down reflex in stimulation mode. Tidal reflexes cause the remaining 95 to 97% of breast milk to be pumped in the expression mode. (Kent JC et al. Breastfeed Med., 2008)

What is the suction and frequency of the NurtureGoods Smart 1.0, Smart 2.0, and Smart 3.0?
The NurtureGoods breast pumps have multiple suction settings and modes for both the Smart 1.0, Smart 2.0 and the Smart 3.0. This has been set at 9 modes, with mode 6 being considered most ideal for the largest group of mothers. What is actually the most ideal for you depends on the position up to which you can still comfortably pump. You have to experiment with this yourself. (Know that pumping harder does not lead to more milk, but rather to sore nipples. Pumping should not hurt!) The Smart 1.0 has 2 modes (Stimulation and Expression) and the Smart 2.0 has 3 modes (Stimulation, Expression, Bionic). The Smart 3.0 also has the same three modes. Now you might wonder what these modes mean.

Stimulation mode gently stimulates the milk let-down reflex for natural milk release, while expression mode pumps more forcefully and frequently. Bionic mode mimics a baby's natural suckling rhythm. To keep the comparison as fair as possible we will use the Expression mode on both pumps. This mode provides the most powerful suction.

The following table provides an overview of the suction power and cycles per minute for the Smart 1.0, Smart 2.0 and the Smart 3.0 at Expression mode 6 and suction frequency setting 3. The Smart 2.0 has 3 frequencies where the third frequency gives significantly more suction power and cycles per minute. The Smart 1.0 and 3.0 do not have this feature and will pump at suction rate 3 by default.

Suction power level: 1 to 9
Mode: S (Stimulation mode) / E (Expression mode) / B (Bionic mode)
Suction frequency level: 1 / 2 / 3
Mmhg: suction power of the breast pump
rpm: cycles per minute for one chest.

It is advisable to go into stimulation mode for as many revolutions/cycles per minute as possible with appropriate suction, so that the letdown reflex can be properly elicited in the range of 70-120 cycles per minute & 38 and 195 mmhg suction. After the let-down reflex, you should preferably pump at least 30 cycles per minute around 220 mmhg suction. The actual cpm and suction required depends on individual needs.

The table shows that both the Smart 1.0, Smart 2.0 and the Smart 3.0 are suitable for single to pump. All pumps fall within the required range of at least 70 cycles per minute to induce milk letdown in stimulation mode. After stimulation mode they should reach a minimum of 30 cycles per minute in expression mode. All three also fall within the required range of mmhg (see also "What should you look for in a breast pump?" section in this article). All modes and positions are suitable to achieve this. The Smart 2.0 stands out the most and is very suitable for single breast pumps because of its higher suction power and cycles per minute.

What about double-sided pump? The Smart 3.0 pumps simultaneously, which means that both breasts are stimulated at the same time. The Smart 1.0 and Smart 2.0 both have a changeover pump. This means that they first pump on one side and then the other side. The breasts are hereby vacuum drawn alternately, stimulating them alternately. As a result, the number of cycles per minute must be divided over both breasts. The Smart 1.0 shows that enough cycles per minute can be achieved with enough suction power to pump both breasts alternately.. Prefer wireless and simultaneous pumping? Then precisely the NurtureGoods Smart 3.0 is best suited to meet all your breast pumping needs.

Curious about what other moms are saying about the NurtureGoods Smart 2.0? Read the story of mother Erin, 26 years old and mama of Senn on
Would you rather have the opinions of experts? The NurtureGoods breast pump is frequently mentioned in independent blogs & websites as one of the best breast pumps of 2021: - What are the best pumping devices of 2021?  - Best Breast Pump of 2021 - Best breast pump

Hopefully you've learned something about breast pumps and what to look for when buying the one that's right for you. Want to know more about the different functionalities of the Smart 1.0, the Smart 2.0, and the Smart 3.0? Read the following blog on the NurtureGoods website.


Einar Egnell, Sven Lakartidn. 1956 Oct 5;53(40):2553-64.Links [Viewpoints on what happens mechanically in the female breast during various methods of milk collection.] Article in Swedish] EGNELL E.

Kent, J. C., Mitoulas, L. R., Cregan, M. D., Geddes, D. T., Larsson, M., Doherty, D. A., & Hartmann, P. E. (2008). Importance of vacuum for breastmilk expression. Breastfeeding Medicine, 3(1), 11-19.

J Morton et al. "Combining hand techniques with electric pumping increases the caloric content of milk in mothers or preterm infants" J Perinatology (2012) 32 791-796

Clemons SN, Amir LH, Breastfeeding women's experience of expressing: a descriptive study, Hum Lact. 2010 Aug; 26(3):258-65.

Lawrence R.A. Lawrence RM. Breastfeeding: A guide for the Medical Professional 1999; Mosby, Maryland Heights; page 289ff

Woolridge, M.W. The anatomy of infant suckling, Midwifery 1986; 2,164-71.