A breast pump is a mechanical device that extracts milk

Milk

Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

 from the breast

Breast

The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

s of a lactating

Lactation

Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...

 woman. Breast pumps may be manual devices powered by hand or foot movements or electrical devices powered by mains electricity or batteries.

History

On June 20, 1854, the United States Patent Office issued Patent No. 11,135 to O.H. Needham for a breast pump. Scientific American (1863) credits L.O. Colbin as the inventor and patent applicant of a breast pump. In 1921-23, engineer and chess master Edward Lasker

Edward Lasker

Edward Lasker was a leading German-American chess and Go player. He was awarded the title of International Master of chess by FIDE. Lasker was an engineer by profession, and an author.-Background:...

 produced a mechanical breast pump that imitated an infant's sucking action and was regarded by physicians as a marked improvement on existing hand-operated breast pumps, which failed to remove all the milk from the breast. The U.S. Patent Office issued Patent No. 1,644,257 for Lasker's breast pump. In 1956 Einar Egnell published his groundbreaking work, "Viewpoints on what happens mechanically in the female breast during various methods of milk collection". This article provided insight to the technical aspects of milk extraction from the breast. The Egnell SMB breastpump designed through this research is quite robust and many pumps are still in operation today over 50 years after publication.

Mechanical properties

Mechanically, a breast pump

Pump

A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...

 is analogous to a milking machine used in commercial dairy

Dairy

A dairy is a business enterprise established for the harvesting of animal milk—mostly from cows or goats, but also from buffalo, sheep, horses or camels —for human consumption. A dairy is typically located on a dedicated dairy farm or section of a multi-purpose farm that is concerned...

 production. A misconception is that the breast pump suctions milk out of the breast. A breast pump's job is to trigger the milk-ejection response or let-down. Pumps achieve this by using suction to pull the nipple into the tunnel of the breast shield or flange then release, which counts as one cycle. Thirty to sixty cycles per minute can be expected with better quality electric breast pumps. The breast pump is not as efficient at removing milk from the breast as the nursing baby. Most manufacturers have multiple sizes of nipple tunnels available. These tunnels range in size from 24mm to 36mm.

There are several types of pump mechanisms. Piston pump

Piston pump

A piston pump is a type of positive displacement pump where the high-pressure seal reciprocates with the piston. Piston pumps can be used to move liquids or compress gases.-Types:* Axial piston pump* Radial piston pump...

s draw a piston through a cylinder to create suction. These are generally considered top of the line units. They have characteristics of low speed, high reliability, low noise, and long life. Rotary vane pump

Rotary vane pump

A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside of a cavity. In some cases these vanes can be variable length and/or tensioned to maintain contact with the walls as the pump rotates. It was invented by Charles C...

s use a cam with retractable vanes to create suction. These rotary vane pumps are not widely used anymore. Fast diaphragm pump

Diaphragm pump

A diaphragm pump is a positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or teflon diaphragm and suitable non-return check valves to pump a fluid...

s use a diaphragm that is acted on by a lever, with thousands of cycles per minute. They operate at higher speed and are usually nosier. Slow diaphragm pumps use a large diaphragm operated by a cam or lever to generate suction with each stroke. Pumps have also been designed that use venturi effects powered by a faucet or water stream, wall suction in hospitals, or pumps powered by mothers oral suctioning.

Expressed breast milk storage

The expressed breast milk

Breast milk

Breast milk, more specifically human milk, is the milk produced by the breasts of a human female for her infant offspring...

 (EBM) may be stored and later fed to a baby by bottle. Expressed milk may be kept at room temperature for up to six hours (at 66-72 degrees Fahrenheit, around 20 degrees Celsius), refrigerated for up to 8 days, or frozen for six months in a deep freeze separate from a refrigerator maintained at a temperature of 0 degrees Fahrenheit, −18 degrees Celsius. Expressed milk may be donated to milk banks, which provide human breast milk to premature infants and other high-risk children whose mothers cannot provide for them.

Reasons for use

Women use breast pumps for many reasons. Many women use breast pumps to continue breastfeeding after they return to work

Lactation room

Lactation room is an American term for a private room where a breastfeeding woman can use a breast pump in private one or more times a day.-Purpose:...

. They use the pump to express breast milk which is later bottle fed to their child by a caregiver. A breast pump may also be used to stimulate lactation for women with a low milk supply, or who have not just given birth. A breast pump may be used to relieve engorgement, a painful condition whereby the breasts are overfull, possibly preventing a proper latch by the infant. If an infant does not latch properly for direct breastfeeding, and the mother still desires the benefits of breast milk, she may choose to pump exclusively. If the mother needs to take medication that affects the breast milk and may be harmful to the infant, the mother may "pump and dump" the breast milk to keep up her milk supply during the time period that she is on the medication and may resume nursing after the course of medication is completed. Finally, pumping may be desirable to continue lactation and its associated hormones to aid in recovery from pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

even if the pumped milk is not used.

Manual breast pumps

Manual breast pumps are operated by squeezing or pulling a handle in a repetitive fashion, allowing the user to directly control the pressure and frequency of milk expression. Though manual pumps are small and inexpensive, they can require significant effort and can be tiring because the user provides all the power. This style is recommended for infrequent usage such as when a woman is away from her baby for a single feeding. These pumps may not provide sufficient stimulation and emptying of the breast. It is recommended that "bicycle horn" style manual pumps not be used. Though cheap, they can damage breast tissue and harbor bacteria in the rubber suction bulb, which is difficult to clean.

Foot-powered breast pumps use the same collection tubing and breast horns as electric breast pumps, but are powered by a foot pedal. This eliminates the work of pumping by hand or the need for finding an electrical outlet with privacy.

Electric breast pumps

There are two types of electric breast pumps, hospital grade and personal use pumps. Hospital grade pumps are larger and intended for multiple users. Personal use pumps are smaller and generally intended for one user. Electric breast pumps are powered by a motor which supplies suction through plastic tubing to a horn that fits over the nipple. The portions of the pump that come into direct contact with the expressed milk must be sterilized to prevent contamination. This style provides a lot more suction, making pumping significantly faster, and allows pumping of both breasts at the same time. Electric breast pumps are ideal for when a mother will be pumping daily. Electric breast pumps are larger than manual ones, but portable models are available (e.g. in a backpack or shoulder bag) that allow the mother to transport the pump. Some manufacturers have battery packs or built in batteries to allow portable operation of the pumps. Some electric pumps allow for multiuser operation, requiring only an accessory kit for each user.

Electric breastpumps can also be rented. Rental pumps are many times recommended for mothers or babies with medical problems such as a premature infant or mother on medication that contraindicates breastfeeding. Rental pumps will generally sustain a mothers milk supply better than personal use pumps. Lactation consultants may assist in selection and training in use.

Some breast pumps are designed to be part of a "feeding system" so that the milk storage portion of the pump is the baby bottle used to feed the infant. This allows the milk to be collected in the same bottle that will feed the baby eliminating the need to transfer breastmilk.

Open collection systems vs. closed collection systems

The plastic tubing and horn of an electric breast pump are commonly referred to as the collection system. When this style of breast pump was originally developed, the pump’s suction was supplied through the collection system tubing. This type of collection system design is now referred to as an open system.

Most electric breast pumps feature an open collection systems. A closed collection system has a barrier or diaphragm that separates the pump tubing from the horn. In this design, the suction of the pump motor lifts the diaphragm to create a vacuum within the collection system to extract milk. An open system allows for the free passage of air/suction. Bacteria and viral filters may be present to prevent any contamination or overflow into pump motor. The pump mechanism motor's suction is directly passed to the mothers breast versus indirectly with closed diaphragm systems.

Open collection systems allow for more flow of air/suction and may be more effective for most women. These systems can compensate better for different tissue elasticities and sizes and shape of the breast. When an open collection system is used, the pump’s suction can cause milk to overflow it into the collection system tubing, which may lead to milk particles being drawn into the pump motor. If milk leaks into the pump’s tubing, the tubes should be washed, sterilized and air-dried prior to using the pump again. Failure to thoroughly clean collection tubing may lead to mold growth within the tubing. Some models of pumps have bacteria and overflow filters which prevent milk from entering the tubing.

A subtype of the open collection system is the single user suction source. These type of pumps have added hygienic benefit of all the parts that generate the suction or come in contact with breast milk stay with the mother. The parts that generate the suction are external to the pump, and can be removed, providing outstanding protection against cross contamination. These pumps are rental or hospital grade breast pumps. Using a pump of this type virtually eliminates the chance of cross contamination of the pump from mother to mother.

The diaphragm in a closed system eliminates the possibility of milk being able to overflow into the pump tubing. Because milk is not exposed to the pump motor, closed collection systems are marketed as more hygienic than open collection systems. It is important to clean the diaphragm as condensation or milk may reach this part causing bacterial contamination. If the diaphragm is contaminated this may defeat the purpose of the closed system. The barrier in a closed collection system breast pump is marketed as preventing outside air from contaminating the expressed breastmilk in the collection bottle, which preserves the milk’s purity. The diaphragm may limit the amount of air/suction that can be used to extract milk from the breast. It may also not be able to compensate for larger shield sizes as well. There are no studies comparing the open versus closed system design. Most information is marketing materials without studies to back them up.

External links

• La Leche League International breastfeeding/pumping support site
• Collecting and storing breastmilk - California Department of Health Services
• Storing Breast Milk/Thawing Frozen Breast Milk - City of Toronto Health Department
• Human Milk Storage Information - La Leche League International