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Babylist Gear Glossary: Breast Pumps
Updated on
November 3, 2023

Babylist Gear Glossary: Breast Pumps

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Babylist Gear Glossary: Breast Pumps.
Babylist Gear Glossary: Breast Pumps

No-rethread harness. Anti-colic vent system. Stability Leg. Flip-flop friendly break.

Ever feel like baby gear lingo is written in a completely different language—one you never learned?

The Babylist Gear Glossary is your one-stop resource to help you unlock the techie terms and insider jargon you’ll run into as you build your baby registry and shop for gear. The series breaks down what you need to know about all things baby gear in short, easy-to-digest definitions and explanations. Each glossary covers a different category like car seats, strollers, baby carriers and more.


Regardless of how you decide to feed your baby, odds are you’ll run into a breast pump somewhere along the way. And truthfully, especially during the fourth trimester, breast pumps can feel like…a lot. There are so many parts! Tons of settings! Too many things to wash! And a pile of terms you’ve never even heard of let alone are able to define.

Familiarizing yourself with your breast pump’s parts—and their function—can help take a little stress out of what can feel like a very daunting task for many pumping and nursing parents.

Breast Pump Parts Glossary

Backflow Protector: A backflow protector is the part of the breast pump that acts as a barrier between the pump and your milk in a closed system breast pump, preventing milk from entering your pump’s motor or tubing. Certain parts of your backflow protector should be replaced regularly, depending on the manufacturer’s recommendations and how often you pump.

Breast Milk Collection Bottles/Containers: Sometimes also called breast milk storage bottles/containers, breast milk bottles are used to collect and store pumped breast milk. Most breast pump kits come with at least two storage bottles, with the option of purchasing more separately. You can pump directly into breast milk storage bottles and use the milk immediately or store it for later use. Another way to store pumped breast milk is with breast milk storage bags, which come in both disposable (plastic) and reusable (silicone) options.

Breast Pump: A breast pump is a device used to extract milk from breasts. There are five types of breast pumps: hospital-grade pumps (heavy-duty and powerful); electric (operate via electricity or batteries); wearable electric breast pumps (hands-free, portable pumps); portable breast pumps (similar to traditional electric breast pumps, but more compact); and manual pumps (pumps that use the motion of your hand to create suction and pump milk).

Breast pumps can be used for a number of different purposes, including to exclusively pump breast milk, to boost or maintain supply or to relieve engorged breasts. Breast pumps are medical devices regulated by the U.S. Food and Drug Administration (FDA). Thanks to the Affordable Care Act (ACA) passed in 2010, health insurers must cover the cost of a breast pump. (The type of pump you qualify for will depend on your particular plan.) You can also check Babylist Health; just input your state of residence and your insurance provider and Babylist Health will do the rest, including providing you a list of covered pumps (including upgrade options if you want to pay more), verifying your insurance coverage, requesting the prescription from your doctor and shipping the pump right to your door.

Breast Shield: A breast shield is also called a flange and is a funnel-shaped part that goes around your nipple and areola and cups your breast while pumping milk. Breast shields are most commonly made from plastic or silicone and come in various sizes. Some breast pumps come with multiple flanges in different sizes, while other pumps require you to purchase them separately. It’s important to use a properly fitted breast shield both for comfort and to maximize milk output. Most brands have specific breast shield sizing guides that show you how to measure and how to choose the correct size.

Connector: Connectors do what their name implies—connect a breast pump’s tubing, breast shield, valve and membrane to the pump’s milk storage bottles. Depending on the breast pump brand you own, the connector may come attached to the breast shield or be separate.

Closed System Pump: There are two types of breast pump systems: closed system and open system pumps. A closed system pump means there is a barrier between the breast pump and its parts and your milk, preventing any leaks or overflow into the pump itself. This barrier also prevents moisture from building up in your pump’s tubing. Most experts and lactation consultants recommend closed system pumps due to a smaller chance of contamination.

Double Electric Pump: A double electric pump is an electric breast pump that allows you to pump both breasts simultaneously. Double electric pumps come with two sets of pump parts, including breast shields, tubing, milk collection bottles and any other necessary components. Double pumps are efficient and can help you save time when pumping.

Expression Phase: When babies nurse at the breast, there are two phases: stimulation phase, when the baby sucks quickly to stimulate milk production, and expression phase, when milk begins to flow and your baby’s suck slows as they take in more milk. Many breast pumps mimic these phases with their suction strength and speed. A pump’s expression phase has longer, slower and stronger suction patterns to mimic how baby would nurse and draw out more milk from your breasts.

Flange: See definition for breast shield above.

Hospital-Grade Breast Pump: A hospital-grade breast pump is a powerful breast pump designed to be used by multiple users in a hospital setting. (Although many hospitals offer monthly rental programs for hospital-grade pumps if you’d like to use one at home.) Some common reasons a pumping parent may choose to use a hospital-grade pump include if their baby is in the NICU or experiencing feeding difficulties, for multiple births like twins or triplets, by recommendation from a lactation consultant for increasing milk supply or simply if a parent prefers this type of pump. Hospital-grade pumps are closed system pumps and feature more powerful motors and many suction levels to maximize milk output. They’re also much larger and heavier than traditional breast pumps. Many insurers will cover the cost of a hospital-grade pump rental if deemed a medical necessity.

Manual Breast Pump: A manual breast pump is a motorless pump that uses either the power of your hand or the pump’s own suction to remove milk. Manual pumps are smaller, lighter, more compact and more affordable than most electric pumps and are ideal for occasional pumping sessions and pumping on the go or for removing milk on one side if your baby is feeding on the other.

Membrane: A membrane is a small part that attaches to a pump’s valve. Membranes act as a barrier between the pump’s tubing and breast milk. Like several other pump parts, membranes wear out over time and need to be replaced per the manufacturer’s recommendation in order to maintain a pump’s suction power and keep it operating optimally over time.

mmHg: An abbreviation for millimeters of mercury, mmHg is a measurement of pressure. mmHg is the standard unit of measurement for a breast pump’s suction level. Suction levels vary from pump to pump, but most have an mmHg level of 220 to 350 mmHg.

Open System Pump: An open system breast pump is the opposite of a closed system pump. An open system pump does not have a barrier between the pump and your milk. Experts note that you should never purchase or use an open system breast pump secondhand for sanitary reasons. If you do choose an open system pump, be sure to closely follow the manufacturer’s directions for sanitizing and cleaning your pump and all of its parts.

Single Electric Pump: A single electric pump is an electric breast pump that pumps one breast at a time.

Stimulation Phase: As noted above, many breast pumps mimic the way a baby would nurse at the breast and have two phases of suction: expression and stimulation. In the stimulation phase, also called the massage phase by some pump manufacturers, many pumps will produce short, quick bursts of suction to stimulate your breasts to start producing milk. Some pumps will feature adjustable vibration settings as well to further stimulate let-down.

Suction: Suction refers to the speed and strength of a breast pump. Also called vacuum strength, most breast pumps have adjustable suction levels. Suction level preferences vary by person. The optimal suction level is generally one that is strong enough to extract the most milk in the shortest amount of time but is still comfortable for the pumper.

Tubing: Breast pump tubing connects the breast shield to the main body of a breast pump. Tubing is clear and flexible and should always be kept clean and dry to prevent mold or bacteria growth.

Valve: Also called a duck or duckbill valve, these small, flexible parts stretch and release each time your breast pump suctions, helping to draw out milk. Valves should be replaced regularly to help keep your breast pump functioning properly; consult your manufacturer’s guidelines as to how often.

Other Common Breast Pumping Terminology

Engorgement: When breasts become overly full with milk, they are considered engorged. Engorgement can happen for a variety of reasons, including during the first few months postpartum when your supply is still regulating, if you’ve gone too long between nursing or pumping sessions or if your baby suddenly starts nursing less than usual or taking in less milk.

Exclusive Pumping: Sometimes abbreviated as EP, exclusive pumping refers to a pumping person who exclusively pumps breast milk with a breast pump to feed their baby.

Galactagogues: A galactagogue is a substance used to induce, maintain or increase the production of breast milk. A galactagogue can include food, medication or supplements.

Hand Expression: Hand expression is the expression of breast milk using your hands. Expressing breast milk by hand is a good skill to learn if you’re a nursing parent both in case of an emergency (if you don’t have access to a breast pump or are unexpectedly away from your baby for a long period of time) and for convenience and comfort.

IBCLC: IBCLC stands for International Board Certified Lactation Consultant. IBCLC is the highest level credential for healthcare professionals who specialize in lactation. An IBCLC can help with any and all lactation issues, including things like breastfeeding pain, low milk supply, latch issues, nursing positions and much more. You can find an IBCLC via the IBCLC Directory, the La Leche League or via a recommendation from a healthcare provider such as your ob-gyn or pediatrician.

Lactation Consultant: Also called lactation support providers, a lactation consultant is a person who is trained in providing support to lactating people.

Let-down: The let-down reflex, also called the milk-ejection reflex (MER), refers to a physiological reflex in which milk is released from the breast. When your baby latches and begins to suck (or when you begin using a breast pump), nerves send a message to your brain to release the hormones prolactin and oxytocin, which then cause milk to flow from your breasts. Some nursing or pumping parents feel their let-down each time it occurs, while others feel nothing at all.

Mastitis: According to the Mayo Clinic, mastitis is an inflammation of breast tissue that sometimes involves an infection. Mastitis can cause breast pain, swelling and redness as well as a fever and chills. You should always call your doctor if you have any symptoms of mastitis.

Milk Ducts: Milk ducts are small tubes that carry milk from the lobules (small sections of breast tissue with glands that produce milk) to the nipples.

Nipple Shield: A nipple shield can be used to help a baby who is learning to nurse. It’s a very thin, flexible piece of silicone that is placed around the areola and nipple. It can help a baby who may be having trouble properly latching to the breast or may have other feeding issues. Nipple shields should be used temporarily and with the help of a lactation consultant.

Nursing Bra: A nursing bra is a bra that’s specially designed to provide easy access for nursing with pull-down or push-aside cups. Nursing bras come in all styles and shapes. Most adjust easily to accommodate postpartum size fluctuations and some are designed to wear overnight or if you’re pumping.

Nursing Pads: Nursing pads address a common issue of nursing parents: leaking. Nursing pads are made from absorbent fabric (usually cotton or bamboo) and are designed to soak up any excess liquid from your breasts. They slip right into your bra and are soft on sensitive skin.

Oxytocin: Oxytocin is a hormone. It’s responsible for causing contractions during labor and for stimulating the release of milk into breast ducts during nursing. It is sometimes referred to as the “love hormone.”

Prolactin: Prolactin is the hormone that’s responsible for lactation and certain breast tissue development. Prolactin levels spike when your baby begins suckling then drop back down when you’re not breastfeeding.


Jen LaBracio

Senior Gear Editor

Jen LaBracio is Babylist’s Senior Gear Editor, a role that perfectly combines her love of all things baby gear with her love of (obsessive) research. When she’s not testing out a new high chair or pushing the latest stroller model around her neighborhood, she likes to run, spin, listen to podcasts, read and spend time at the beach. In her past life, she worked for over a decade in children’s publishing. She lives outside of Chicago with her husband and their two boys, Will and Ben.

This information is provided for educational and entertainment purposes only. We do not accept any responsibility for any liability, loss or risk, personal or otherwise, incurred as a consequence, directly or indirectly, from any information or advice contained here. Babylist may earn compensation from affiliate links in this content. Learn more about how we write Babylist content and review products, as well as the Babylist Health Advisory Board.