Moms often feel that the stronger a breast pump the better. But before you put that breast pump on the highest setting, make sure you know the benefits (and risks) before going all-in on strength.

How Breast Pump Suction Is Measured

Breast Pump power of suction is usually documented as mmHG which is millimeters of mercury, the standard unit of measuring vacuum pressure. When you’re buying a breast pump, you might see mmHg in the product listing. This number, generally in the range of 220 to 350, is the maximum suction level. Aeroflow Breastpumps lists the maximum strength of all breast pumps on their Breast Pump Comparison Chart.

Breast Pump Suction = Baby’s Natural Sucking

Breast pump suction mirrors baby's natural sucking through several phases:

  • Let Down - mimics when baby is vigorously sucking. This phase stimulates the nerves in your breasts, which signals the release of a hormone called oxtyocin. The release of oxytocin will make the small muscles that surround your milk-producing tissue to contract, which squeezes milk into your ducts. 
  • Expression - mirrors when baby's sucking slows down, and he/she is swallowing milk. This is sometimes called "suck, pause, swallow."

Some pumps have vacuum suction patterns that are meant to mirror the movements of an infants tongue- called "undulation", with the goal is to reproduce the pattern of older infants sucking that can trigger multiple letdowns. Babies who are a month and older will typically alternate between a light and fast "flutter sucking" to a deep and rhythmic sucking pattern, and occasionally when flow changes suck with both intensity and speed. Alternating back and forth between similar patterns on a pump can help to trigger multiple let downs and thus express more milk than if there is just one let down.

When To Go Low (Or High)

Mother using pump with optimal suction strength

When establishing supply, especially in situations where the pump is replacing direct breastfeeding, such as separation from mother and baby in the first week after birth, baby unable to latch and suck adequately, or any other reason why a parent would be exclusively pumping, a pump with higher strength and efficiency is what is needed to make sure that the body receives adequate signals to increase breast milk volume and to transition from colostrum to mature milk.

In other situations, such as the occasional pumping for a night out, or someone who is working part-time but breastfeeding the majority of the time, a pump with more mild settings should be adequate. A pump with 150mmHg is recommended for any situation where parents will be pumping on a regular basis so that at least supply can be maintained when baby is not able to directly breastfeed.

And remember, high breast pump suction can actually hinder milkflow by causing the breast tissue to compress too much, cutting off flow in the milk ducts. If you're experiencing pain while pumping, turn down the suction level. Pain reduces the amount of oxytocin your body makes in response to stimulation, which then would slow milk synthesis and instead raise cortisol to tell you: “HEY! This hurts!”

Is Strength The Issue, Or Is It Something Else?

For many moms who think there is a problem with their suction, it could actually be the fit of your flange/breastshield, so it’s important you have the right fit. If this is your first time using the pump, see a lactation specialist to make sure your flanges are the right fit for your nipple size and shape as well as areola density and fullness. Believe it or not, just any variation or mismatch in those things would make a difference in proper suction due to the fact that the flange may not have correct contact with the nipple or breast tissue. The other thing to do would be to consult the brand’s fitting guide.

Breast pumps come with different strengths because every woman's breastfeeding journey is different, and one size does not necessarily fit all. Bottom line, when it comes to pump strength versus suction efficiency, it’s brains over brawn in every way.

Information provided in blogs should not be used as a substitute for medical care or consultation.

Author Leah DeShay    

Leah DeShay

Leah graduated from La Sierra University and it was during her undergraduate studies that she found her passion for women’s health care. She completed her post-baccalaureate work in Lactation at the University of California, San Diego, holds a CLEC (Certified Lactation Educator Counselor certificate, and is an IBCLC (Internationally Board-Certified Lactation Consultant).