Now that we understand how breast pumps draw milk out of the body and into bottles and containers, let's examine the different available types:
Manual pumps: As mentioned in the previous section, these devices run on old-fashioned elbow grease. The user creates suction by squeezing a lever or handle or pumping a cylinder-shaped tube within a larger cylinder (a piston) [source: FDA]. There are also foot-pedal pumps that rely on lower-body strength to create suction. Once let-down occurs, milk collects in attached containers. Manual pumps are small, discrete and relatively inexpensive; however, they work slower than other pumps and can cause strain because the user provides all the power.
Battery-powered pumps: This option relies on a small motor -- connected to the breastshield by plastic tubing -- usually powered by AA or C batteries. Because it can take 10 to 50 seconds to reach optimum vacuum, these pumps might cycle about 10 times per minute [source: Knorr]. That's not too fast if you remember that babies' nurse about 50 to 90 times per minute at the beginning of a feeding. These pumps can be uncomfortable (because of the constant vacuum) and take more time, but they're portable, affordable and work anywhere. With a hands-free pump, which fits inside a bra and comes with an AC adapter, the milk slowly travels from a flexible valve stem into a bag [source: Consumer Reports].
Electric pumps: Out of the three types, electric pumps are the most efficient and the most expensive. A cord connects the motor to an electrical outlet, allowing enough power to drain breasts quickly and completely. Women can achieve total efficacy by double pumping both breasts at the same time, usually at a rate of about 40 to 60 cycles per minute. Users are also able to customize suction rhythm by adjusting the settings. A powerful hospital-grade pump, available for rent and for users in medical facilities, is a good option if your baby has a hard time latching on or you don't plan on pumping for more than three months [source: Consumer Reports]. If you plan on expressing your milk longer than that or will be returning to work, consider personal-use automatic pumps. Like their hospital-grade counterparts, personal-use pumps reduce pumping time and feature individualized settings. As the name implies, these lightweight pumps, which usually come in discrete backpacks and tote bags, and can't be shared as hospital pumps can. Some of these pumps come packaged with manual pumps as well.