You would think that the stronger is better. But I’m telling you: don’t suck your brains out your nipples. Breast pump suction power is measured in mmHG (millimeters of mercury), the standard unit of measuring vacuum pressure. Studies were done on babies sucking at the breast and breasts pump suction levels are based off that. The suction level, or vacuum, is different than the cycle speed, which is how fast it pumps. Most pumps will cycle at 40-70 cycles per minute. This is based off of the average number of sucks a baby does at the breast in that same amount of time. Every baby sucks are their own pace and with their own vacuum strength.

Each pump has its own max suction strength. “Hospital grade” pumps generally have maximum suction levels in the 300+ mmHg range while personal grade pumps are generally in the 200+ mmHg range. This doesn’t necessarily make a pump better or worse. The highest suction level on many pumps are actually above the comfort zone of the majority of pumpers. Most people feel comfortable expressing in the range of 150 – 200 mmHg regardless of whether the pump can reach 250 or 350 mmHg at its max.

Think of pumping like drinking from a milkshake with a narrow straw. When you suck too hard, the straw collapses on itself and the shake is really hard to drink. Milkshakes move better with gentle, consistent sucking that doesn’t collapse the straw. Milk ducts are like compressible straws inside the breast. Not only does everyone have a different number of these ducts, but the diameter of the ducts also varies from person to person.

Too much breast pump suction compresses the areolar tissues which pinches off the ducts and decreases the flow of milk to the pump. With time this can cause milk to back up in the breast, increasing the risk of plugged ducts/mastitis. This also leaves milk behind which eventually can drop your overall milk supply. This can also damage the nipple. Having the right size flange AND using enough suction to move milk but not compress the ducts is essential to a happy pumping journey.